The Mars Curse is the term used to describe the inordinately high failure rate for missions to our red celestial sister, particularly those that dare to touch the surface. It’s an inherently complicated mission as there are innumerable things that need to be taken into account in order to get something on the surface and a problem with any one of the systems can result in a total mission failure. One such mission that fell prey to this was the European Space Agency’s Beagle 2, a small lander that hitched a ride with the Mars Express craft all the way back in 2003. Shortly after it was sent down to the surface contact with the probe was lost and it was long thought it met its end at an unplanned disassembly event. However we’ve recently discovered that it made all the way down and even managed to land safely on the surface.
Like the Mars Exploration Rovers Beagle 2 would use the martian atmosphere to shed much of its orbital velocity, protected by its ablative heat shield. Once it approached more manageable speeds it would then deploy its parachutes to begin the final part of its descent, drifting slowly towards the target site. Then, when it was about 200m above the ground, it would deploy airbags around its outer shell to protect it from the impact when it hit the surface. Once on the ground it would then begin unfurling its solar panels and instrumentation, making contact with its parent orbiter once all systems were nominal. However back on that fateful day it never made contact and it was assumed the lander likely destroyed.
The information we now have points towards a different story. It appears that pretty much everything went according to plan in terms of descent which, as my very high level description of the process can attest to, is usually the part when things go catastrophically wrong. Instead it appears that Beagle 2 made it all the surface and began the process of deploying its instruments. However from what we can see now (which isn’t much given that the lander is some 2m across and our current resolution is about 0.3m/pixel) it appears that it didn’t manage to unfurl all of its solar panels which would have greatly restricted its ability to gather energy. My untrained eye can see what looks like 2 panels and the instrumentation pod which would leave it with about half the power it was expecting.
In my opinion though (which should be taken with a dash of salt since I’m not a rocket scientist) there must have been some damage to other systems, most likely the communications array, which prevented it from making initial contact. I’d assume that there was enough charge for it to complete it’s initial start up activities which should have been enough to make initial contact with the orbiter. Such damage could have occurred at any number of points during the descent and would explain why there was total silence rather than a few blips before it dropped off completely. Of course this is just pure speculation at this point and we’re not likely to have any good answers until we actually visit the site (if that will ever happen, I’m looking at you Mr Musk).
Still discovering Beagle 2’s final resting place is a great find for all involved as it shows what went right with the mission and gives us clues as to what went wrong. This information will inform future missions to the red planet and hopefully one day we can write off the Mars curse as simply a lack in our understanding of what is required for a successful interplanetary mission. Indeed the bevy of successful NASA missions in the past decade is a testament to this constant, self correcting trial and error process, one that is built on the understanding gleaned from those who’ve come before.
Since before the Shuttle’s retirement back in 2011 NASA has been looking towards building the next generation of craft that will take humans into space. This initially began with the incredibly ambitious Ares program which was set to create a series of rockets that would be capable of delivering humans to any place within our solar system. That program was cancelled in 2010 by President Obama and replaced with a more achievable vision, one that NASA could accommodate within its meagre budget. However not all the work that was done on that program was lost and the Orion capsule, originally intended to ride an Ares-I into space, made its maiden flight last week signalling a new era for NASA.
The profile for this mission is a fairly standard affair, serving as a shakedown of all the onboard systems and the launch stack as a whole. In terms of orbital duration it was a very short mission, lasting only 2 orbits, however that orbit allowed them to gather some key data on how the capsule will cope with deep space conditions. It wasn’t all smooth sailing for the craft as the mission was meant to launch the day before however a few technical issues, mostly to do with the rockets, saw NASA miss the initial launch window. However the second time around they faced no such issues and with the wind playing nice Orion blasted off for its twice around the world voyage.
When I first read about the mission I was curious as to why it was launching into such an unusual orbit. To put it in perspective the apogee (the point of the orbit furthest away from the earth) was some 5,800KM which is an order of magnitude higher than anything else in low Earth orbit. As it turns out this was done deliberately to fling the Orion capsule through the lower Van Allen belt. These belts are areas of potentially damaging radiation, something which all intersolar craft must pass through on their journey to other planets in our solar system. Since Orion is slated to carry humans through here NASA needs to know how it copes with this potential hazard and, if there are any issues, begin working on a solution.
The launch system which propelled the Orion capsule into orbit was a Delta-IV Heavy which currently holds the crown for the amount of payload that can be delivered to low Earth orbit. It will be the first and last time that we’ll be seeing Orion riding this rocket as the next flight, slated for launch towards the end of 2018, will be the Space Launch System. This is the launch system that replaced the Ares series of rockets when Obama cancelled the Constellation program and will be capable of delivering double the payload of the Delta-IV Heavy. It’s going to need that extra power too as the next Orion mission is an uncrewed circumlunar mission, something NASA hasn’t done in almost 5 decades.
It’s great to see progress from NASA, especially when it comes to its human launch capabilities. The Shuttle was an iconic craft but it simply wasn’t the greatest way to get people into space. The Orion however is shaping up to be the craft that might finally pull NASA out of the rut it’s found itself in ever since the Apollo missions ended. We’re still a while off from seeing people make a return to space on the back of a NASA branded rocket but it’s now a matter of when, and not if, it will happen.
When you think of scientific telescopes there’s usually only 2 different types that come to mind. The ones down here on terra firma, with their giant white domes covering their precious mirrors, and the ones up in space like the venerable Hubble Space Telescope. Each of these has is set of benefits and drawbacks, like the ground based ones having massive mirrors and the space based ones not having to deal with our atmosphere. However there’s potential for a telescope that straddles the boundaries of these two types of telescopes, one that’s far above the Earth’s surface but also doesn’t require the heavy energy investment of an orbital craft. Indeed NASA has flown craft like these in the past and they’re now looking to airships to fly the next generation of such telescopes.
Ground based telescopes suffer from 2 major drawbacks related to the atmosphere. The first is the aberrations caused by the shifting atmosphere, the same thing that causes the stars to twinkle at night, which makes precise measurements incredibly difficult. The second is that the atmosphere is great at absorbing a lot of the frequencies of light, specifically infrared, something which we can’t really overcome with special optics or filters. Putting a telescope in space negates these problems but brings with it a whole other set of challenges which is precisely why NASA is looking to develop a sub-orbital telescope concept using an airship as the platform.
NASA has constructed platforms like this in the past, the most notable one of which is SOFIA, an infrared observatory that’s built into the back of a Boeing 747. At its cruising altitude it’s able to see 85% of the total infrared light coming to Earth a considerable amount more than any ground based telescope will be able to see. The primary limit to SOFIA is its endurance time which is around eight hours or so although its capability to be pretty much anywhere in the world does make it incredibly flexible in the operations it can perform. The airship design that NASA is looking to pursue would address this limitation whilst providing some other benefits.
Airships, whilst not being as mobile as their winged cousins, have the advantage of being able to stay aloft in a location for extended periods of time that aircraft simply aren’t capable of doing. For an observatory this provides several advantages such as being able to do longer exposures on targets as well as being able to take advantage of higher bandwidth downlinks to their base sites. There are several engineering challenges that will need to be solved before a viable aircraft will materialize, but it’s certainly within the realms of possibility.
Pending funding of the idea NASA will be funding it X-prize style, looking for designs (and I assume workable craft) that can carry a small or large payload up into the atmosphere. Such programs have proved to be highly successful in the past and I’m sure we’ll see some pretty interesting craft come out of it. Considering that SOFIA is slated to be shut down due to budgetary concerns sometime next year a viable alternative needs to be sought so they don’t introduce more holes in their capabilities. Of course getting an airship with a telescope up in the air before that happens isn’t going to be likely but the sooner the process is started the better.
There’s numerous stories about the heydays of rocket engineering, when humanity was toying around with a newfound power that we had little understanding of. People who lived near NASA’s test rocket ranges reported that they’d often wait for a launch and the inevitable fireball that would soon follow. Today launching things into space is a well understood territory and catastrophic failures are few and far between. Still when you’re putting several thousand tons worth of kerosene and oxygen together then putting a match to them there’s still the possibility that things will go wrong and, unfortunately for a lot of people, something did with the latest launch of the Orbital Sciences Antares rocket.
The mission that it was launching was CRS Orb-3, the third resupply mission to the International Space Station using Orbital Sciences Cygnus craft. The main payload consisted mostly of supplies for the ISS including food, water, spare parts and science experiments. Ancillary payloads included a test version of the Akryd satellites that Planetary Resources are planning to use to scout near Earth asteroids for mining and a bunch of nano Earth observation satellites by Planet Labs. The loss of this craft, whilst likely insured against loss of this nature, means that all of these projects will have their timelines set back significantly as the next Antares launch isn’t planned until sometime next year.
NASA and Orbital Sciences haven’t released any information yet about what caused the crash however from the video footage it appears that the malfunction started in the engines. The Antares rocket uses a modified version of the Russian AJ-26 engine who’s base design dates back to the 1960s when it was slated for use in the Russian Moon shot mission. The age of the design isn’t an inherently bad thing, as Orbital Sciences have shown the rockets were quite capable of putting things into orbit 4 times in the past, however the fact that Antares is the only rocket to use them does pose some concerns. The manufacturer of the engines have denied that their engines were to blame, citing that it was heavily modified by Aerojet prior to being used, however it’s still probably too early to rule anything in or out.
One thing I’ve seen some people pick up on is the “Engines at 108%” as an indication of their impending doom. The above 100% ratings typically come from the initial design specifications which aim to meet a certain power threshold. Many engines exceed this when they’re finally constructed and thus any power generated above the designed maximum is designated in this fashion. For most engines this isn’t a problem, the Shuttle routinely ran it’s engines at 110% during the initial stages of takeoff, so them being throttled over 100% during the ascent stage likely wasn’t an issue for the engines. We’ll know more when NASA and Orbital Sciences release the telemetry however.
Hopefully both Orbital Sciences and NASA can narrow down the cause of this crash quickly so it doesn’t affect any of the future CRS launches. Things like this are never good for the companies involved, especially when the launch system only has a handful of launches under its belt. The next few weeks will be telling for all involved as failures of this nature are rarely due to a single thing and are typically a culmination of a multitude of different factors leading up to the unfortunate, explosive demise of the craft.
It did make for a pretty decent light show, though.
It’s been a long time since I wrote about the X-37B, originally NASA’s but now the Department of Defense’s secretive space plane, and that’s mostly because there’s not been a whole lot to report.The secret nature of its mission means that no details about its payload are readily available and unlike the first time it was launched it’s been behaving itself, staying within its own orbit. Still that didn’t stop the Internet from going on a rampage of speculation, the highlight of it being the ludicrous idea that it was spying on China’s efforts in space. However over the weekend it returned from its orbit around the earth after a staggering 2 years on orbit.
Now 2 years might not sound like a long time, especially when the Voyager satellites are pushing 35+ years, however for a craft of this type such a record is a pretty significant advancement. Most capsules and spacecraft that had downrange capacity (I.E. they can bring stuff back) usually have endurances of a couple weeks. Even the venerable shuttle could only last a couple weeks in orbit before things started to get hairy, even if it was docked to the International Space Station. With the X-37B able to achieve an endurance of 2 years without too much of a struggle is a pretty impressive achievement and raises some interesting questions about what its true purpose might be.
The official stance is that it’s a test platform for a whole host of new space technologies like navigational systems, autonomous flight and so on. Indeed from what we’ve seen of the craft it certainly contains a lot of these features as it was able to land itself without human intervention just last week. It’s small payload bay nods towards some other potential purposes (the favourite speculation is satellite retrieval) but it’s most likely just used to house special equipment that will be tested over the duration of the flight. There’s potential for it to house some observational equipment but the DoD already has multiple in-orbit satellites for that purpose and unlike spy satellites of the past (which used film) there’s no real need for downrange capabilities in them any more.
Unfortunately any technological innovations contained within the X-37B are likely to stay there as NASA hasn’t been involved in the X-37B project since it handed it over. It’s disappointing really considering that the DoD has a budget for space activities that equals NASA’s entire budget and there’s definitely a lot of tech in there that they could make use of. Thankfully the private space industry is developing a lot of tech along similar lines so hopefully NASA and its compatriots will have access to similar capabilities in the not too distant future.
Maybe one day we’ll find out the true purpose of the X-37B much like we did with Hexagon. Whilst the story might be of the mundane the technology powering things like Hexagon never ceases to amaze me. If the X-37B is truly a test platform for new kinds of space tech then there’s likely things on there that are a generation ahead of where we are today. We may never know, but it’s always interesting to let your mind wonder about these things.
After their initial flurry of activity launches over 7 years ago Bigelow Aerospace has become rather quiet, cancelling its 2 further prototypes and pursuing other activities. Presumably this was because they were a little ahead of their time as there just wasn’t any private (or public even) launch systems available to take would be space tourists to any of their modules. This, combined with them reducing their staff a couple years ago, meant that their requirements to deliver additional prototypes into space were dramatically reduced and they have instead been focusing on developing their technology with NASA. Now it seems, after almost a decade since their first launch, Bigelow will be making their return into space next year with the Bigelow Expandable Activity Module (BEAM).
The BEAM is probably derived from Bigelow’s Galaxy craft as it shares much of the same characteristics as that prototype was slated to have. Comparatively it’s a small part of the ISS, coming in with 16m³ worth of liveable volume, but it will contain all the elements necessary to support astronauts on orbit. For the most part it will be a demonstration and testing module, designed to measure things like leakage rates, radiation exposure levels and testing all the systems required to maintain it. The total mission duration is set for 2 years with the astronauts only entering it on occasion. The results from this will likely end up heavily influencing Bigelow’s next module, the behemoth of the BA330.
The total cost of the module is, by ISS standards, a steal coming in at just over $17 million. Although this doesn’t include the launch cost which, considering that it’s on the back of a Falcon-9, would likely be around $54 million putting the total cost at about $71 million. Still even if the further missions doubled the cost of the module you’d still be looking at an incredibly cheap way to add liveable volume to the ISS, something which is very much at a premium up there. More though it makes Bigelow’s Commercial Space Station seem that much more feasible as previously the amount of capital required just to get their modules into space was very cost prohibitive.
The BEAM module won’t be a one shot wonder, however. Bigelow plans to build another one of the modules to serve as an airlock on its future space station which would allow up to 3 astronauts (or more likely, space tourists) to space walk at a time. The ISS can currently handle only 2 astronauts at a time so it’s definitely a step up and I can imagine NASA acquiring another BEAM type module in the future if they were looking to expand the ISS’ operations. It might not sound like much but it could drastically reduce the amount of spacewalking time that astronauts have to undertake, which can sometimes be up to 10 hours at a time.
It’s great to see Bigelow back in the game again with firm timelines for delivering modules into space. The fact that they’ll be delivering capability to the ISS is even better as there’s huge potential for NASA to increase the lifetime of our only space station using Bigelow’s technology. Whilst no space launch date is ever set in stone I’m hopeful that we’ll see BEAM attached to the ISS in the not too distant future and, hopefully, the BA330 not too long thereafter.
The boom that 3D printing has experienced over the past couple years has been nothing short of astonishing. The industry started off as predominately as a backyard engineering operation, designing machines that’s sole purpose was to be able to print another one of itself, but it quickly escalated into the market we know today. Indeed it seems even the most wildest predictions about how it would revolutionize certain industries have come true with leading engineering companies adopting 3D printers for both prototyping and full blown production developments. With that in mind it was only a matter of time before one of them was bound for the International Space Station and yesterday SpaceX launched the first 3D printer to be based in space.
The printer, made by Made in Space, isn’t simply a stock standard model that’s been gussied up to work on the ISS. It’s been specifically designed to work in the microgravity environment in low earth orbit, undergoing thousands of simulated zero-g tests (presumably on one of NASA’s vomit comets). Whilst the specifications might not be exactly astounding when compared to some of the printers available down here on earth, it only has a print volume of 5cm x 10cm x 5cm with ABS plastic, it has the potential to be quite revolutionary for NASA, not to mention 3D printing at large.
One of the worst things about space travel is having to bring everything you need with you as there’s really no manufacturing capability to speak of in space. A 3D printer however provides the opportunity to ship up bulk supplies, in this case large reels of ABS plastic, which have a much greater density than the parts created with them will have. This drastically reduces the cost and complexity of shipping things up into space and provides a greater opportunity to create things in-orbit that might not be feasible to ship up otherwise. Of course whether or not 3D printing will be viable in space is another question, one which this device will attempt to answer.
There’s a lot of use for 3D printed plastic parts on the ISS, notably pretty much any small clip or connector on the interior of the craft, however I feel that the real usefulness of 3D printer will come when they can print with metal. Right now there’s no good solutions for doing that via the extruder (although there are a few out there using solder, which doesn’t have the greatest construction properties) as most use the powder bed sintering process. As you can probably guess having a bunch of powder in a microgravity environment isn’t going to work out too well so I’ll be interested to see how future space based 3D printers deal with metal and other materials.
It’s really quite exciting to see developments like this as there’s an incredible amount of opportunity for 3D printing to revolutionize several aspects of space travel. Indeed for long duration missions, one where component failure is a real risk, these kinds of in-orbit manufacturing capabilities are a necessity. Whilst we won’t be mass producing spacecraft parts in orbit any time soon these are the first few baby steps needed to developing that capability.
And wouldn’t you know it Planetary Resources already has partnerships in that direction. I should have guessed!
As of right now there’s only one way to get humans into space: on board a Russian Soyuz craft. It’s an incredibly reliable spacecraft, and probably one of the longest serving spacecraft ever, however it’s ability to only send up 3 astronauts at a time does limit it’s capabilities. Couple that with the fact that the going rate for a seat on one of them is about $70 million you can imagine why there’s an imperative on NASA to find another way to get themselves up there. Whilst there’s been a lot of internal work to develop the next generation of crew transportation NASA has realised that the private space industry will very soon have that capability. To that effect they created the Commercial Crew Transportation Capability (CCTCap) award, a $6.8 billion dollar contract to provide crew transportation services.
Today they announced the winners: SpaceX and Boeing.
The contract split gives $2.6 billion to SpaceX and $4.2 billion to Boeing. Considering NASA’s long relationship with Boeing it’s not surprising that they got a larger chunk of the pie (and the fact that they’ve already sunk about half a billion into the program already) however I’m sure SpaceX won’t be unhappy with that much business coming their way. Both companies are already well underway with their respective crew transports, Boeing with the CST-100 and SpaceX with the Dragon, which is likely why they were chosen in the first place. This program won’t replace the work that’s currently being done by NASA with the Orion capsule (under contract with Lockheed Martin) and will instead function as a supplement to that capability.
Being awarded work under CCTCap isn’t all roses however as NASA is looking to have at least one of the capsules up and running by 2017. That largely lines up with the timelines that SpaceX has for their Dragon capsule, with the first flights scheduled for late next year with crewed missions to follow shortly after. As to how that fits with the current CST-100 schedule is less clear as whilst there’s been some mockup tests done a couple years ago I haven’t seen much progress on it since. Boeing isn’t the same kind of company that SpaceX is though so there’s every possibility that the CST-100 is just as far along its development pipeline as the Dragon is. Still the CCTCap only calls for one of them to be ready by that time and if I was a betting man my money would be on SpaceX.
Both company’s solutions are of the reusable capsule variety which might seem a step backwards but it’s actually the smarter way to do space travel, especially if cost is a primary factor. The Space Shuttle, whilst iconic in its shape and unmatched in its capabilities, was a compromise between far too many objectives that were at odds with each other. If you’re goal is just getting people up and down then capsules are the way to go. It will be interesting to see if the economies of scale kick in with these craft as the Dragon is designed to be launched many times per year and the CST-100 can be reused up to 10 times before it needs a full teardown.
Needless to say this is an incredibly exciting announcement. I’ve long been of the mind that NASA should leave things like this to the private companies who can deliver the same service at a much better price without compromising on saftey. That then leaves them free to do the big picture stuff that will inspire the next generation, the kinds of things that we all remember the NASA name for. The CCTCap is the first step towards them rekindling that spirit and, as an avid space geek, that makes me so wonderfully happy.
One of the biggest limitations on spacecraft today is the fact that you have to carry your fuel with you. The problem is that fuel is heavy and the more fuel you want to take with you means more fuel needed to get it up there, compounding the issue. There are some novel engines that combat this problem like the Ion Thrusters which are extremely fuel efficient, able to achieve massive delta-v over long periods of time. They still require fuel to be brought with them however and their performance characteristics don’t lend them to being useful for anything but long duration robotic missions. So there’s been something of a quest to find an engine that has similar properties that could potentially be used for more timely adventures and the latest candidate in that arena is the Cannae Drive. Although many sites have been hailing this as an “impossible” kind of drive that’s a little misleading as it was essentially an unproven theory with an unknown mechanism of action. The Cannae Drive (the latest variant of what’s called an EmDrive) uses a magneton to produce microwaves inside a specially designed vessel that’s tapered out to be larger at one end. The theory goes that this will then produce a net thrust in the desired direction even though no detectable energy leaves the device. Upon hearing that I can see why many people would say that it’s impossible however the latest results from NASA would suggest that the idea may have some merit to it, at least enough to warrant further investigation.
Eagleworks, the informal name for the Advanced Propulsion Physics Laboratory at NASA, has test all sorts of exotic propulsion devices including the original EmDrive design. The Cannae Drive has a much flatter resonant cavity when compared to the EmDrive, slightly degrading some of the performance characteristics (although what benefits it gives I can’t seem to find out), and the design called for radial slots along the bottom side of the vessel in order to be able to produce thrust. To properly test this theory NASA also tested a “null” vessel that lacked the slots. However both vessels produced a thrust, something which throws a wrench into the proposed mechanism of action.
Essentially it means one of two following things are true: the thrust produced is anomaly of spurious effects and mathematical errors or the mechanism of action proposed is wrong and something completely different is responsible for it. The former explanation is starting to look less appealing as there’s been several positive results with the engine thus far. It’s entirely possible that the original theory behind the mechanism of operation was wrong and there are numerous tests that can be done in order to ascertain just what makes this thing tick. Eagleworks don’t seem to be satisfied with their current answer so I’m sure we’ll be hearing more about this engine in the not too distant future.
If this, or any of the other reactionless drives, come to fruition it will be a major boon for the space industry as there are numerous applications for propulsion that doesn’t require fuel to drive it. Things like geostationary satellites, which currently have a limited life thanks to the station keeping required to keep them there, could benefit greatly from this extending their usable lifetimes far beyond the current norm. It would also open the possibility of ever more ambitious exploration goals, allowing us to explore the solar system in ways that are just simply not possible today. Between then and now though there’s a lot of science to be done and we should be all glad that NASA is the one on the case.
Ever since the retirement of the Space Shuttle the USA has been in what’s aptly describes as a “launch gap”. As of right now NASA is unable to launch its own astronauts into space and instead relies completely on the Russian Soyuz missions to ferry astronauts to and from the International Space Station. This isn’t a particularly cheap exercise, coming in at some $70 million per seat, making even the bloated shuttle program look competitive by comparison. NASA had always planned to develop another launch system, originally slated to be dubbed Ares and developed completely from scratch, however that was later scrapped in favour of the Space Launch System which would use many of the Shuttle’s components. This was in hope that the launch gap could be closed considerably, shortening the time NASA would be reliant on external partners.
News comes today that NASA has approved the funding for the project which is set to total some $6.8 billion over the next 4 years. The current schedule has the first launch of the SLS pegged for some time in 2017 with the first crewed mission to follow on around 4 years later. Developing a whole new human rated launch capability in 7 years is pretty good by any standards however it also begs the question as to whether or not NASA should be in the business of designing and manufacturing launch capabilities like this. When Ares and SLS were first designed the idea of a private company being able to provide this capability was still something of a fantasy however that’s no longer the case today.
Indeed SpaceX isn’t too far off deploying their own human rated craft that will be capable of delivering astronauts to the ISS, Moon and beyond. Their current schedule has the first crewed Dragon flight occurring no sooner than 2015 which, even with some delays here and there, would still have it happening several years before the SLS makes its manned debut. Looking at the recent Dragon V2 announcement it would seem like they’re well on their way to meeting those deadlines which will give the Dragon several years of in-flight usage before the SLS is even available. With NASA being far more open to commercial services than they used to be it does make you wonder what their real desire for the SLS is.
There’s an argument to be made that NASA has requirements that commercial providers aren’t willing to meet which, when it comes to human rated vessels, is mostly true. Man rating a launch system is expensive due to the numerous requirements you have to meet so most opt to just not do it. SpaceX is the notable exception to this as they’ve committed to developing the man rated Dragon even if NASA doesn’t commit to buying launches on it. Still the cash they’re dropping on the SLS could easily fund numerous Dragon launches, enough to cover NASA off for the better part of a decade if my finger in the air maths is anything to go by.
The only argument which I feel is somewhat valid is that NASA’s requirement for heavy lift outstrips pretty much any commercially available launch system available today. There’s really not much call for large single payloads unless you’re shipping humans into space (we’ve got an awfully long list of requirements compared to our robotic cousins) and so most of the big space contractors haven’t built one. SpaceX has plans to build rockets capable of doing this (the Falcon XX) although their timeframes are somewhat nebulos at this point in time. Still you could use a small portion of the cash set aside for the SLS in order to incentivise the private market to develop that capability as NASA has done quite successfully with its other commercial programs.
I’ve long been of the mind that NASA needs to get out of the launch system business so they can focus their time and resources on pushing the envelope of our capabilities in space. The SLS might fill a small niche that’s currently unserviced but it’s going to take its sweet time in getting there and will likely not be worth it when it finally arrives.