What should NASA actually do with SLS?

[Vahe231991]

Alexw, the rest of us define it by the number of launches required. No gray areas there.

Did anyone put out proposals for asteroid defense?

I know that we have already some coordinated efforts to identify potentially threatening objects; is there any possibility about doing something with 70MT to orbit, and maybe propellent depots? This is blue sky, and we'd better not need it before 2017, but still, is there anything we reasonable do about it with SLS capability?

This thread may be old, but with respect to the first two questions, but in January 2012 a near pass-by asteroid 2012 BX34 prompted the publication that year of a paper titled "A Global Approach to Near-Earth Object Impact Threat Mitigation" by researchers from Russia, Germany, the United States, France, Britain, and Spain, which dealt with the "NEOShield" asteroid defense project. The DART spacecraft was proposed in the mid-2010s and it was launched in November 2021 and successfully hit the asteroid Dimorphos on September 26, 2022.

Links:
https://www.space.com/14370-asteroid-shield-earth-threat-protection-meeting.html
https://web.archive.org/web/20150607004851/http://www.esa.int/Our_Activities/Space_Engineering_Technology/NEO/Asteroid_Impact_Deflection_Assessment_AIDA_study

[spacenut]

Back in 2010, they thought SLS would be cheaper and more sustainable.  Today, it is not.  It has become too expensive to launch more than once a year.  Solids are expensive and not reusable.  They cost as much to refurbish as new ones.  Hydrogen is not a good booster fuel.  Is expensive and only good for upper stages.  All the new rockets are using methane, Starship/superheavy, Vulcan, New Glenn, and some small startups.  Clean, more power than hydrogen, and is great for reusable engines as there is no coking like kerosene.  SpaceX has proven you can land a booster which is the largest and most expensive part of getting to orbit.  Now we have to reuse upper stages/spacecraft.  NASA did not go this route because of congress who appropriates the money. 

[TrevorMonty]

Back in 2010, they thought SLS would be cheaper and more sustainable.  Today, it is not.  It has become too expensive to launch more than once a year.  Solids are expensive and not reusable.  They cost as much to refurbish as new ones.  Hydrogen is not a good booster fuel.  Is expensive and only good for upper stages.  All the new rockets are using methane, Starship/superheavy, Vulcan, New Glenn, and some small startups.  Clean, more power than hydrogen, and is great for reusable engines as there is no coking like kerosene.  SpaceX has proven you can land a booster which is the largest and most expensive part of getting to orbit.  Now we have to reuse upper stages/spacecraft.  NASA did not go this route because of congress who appropriates the money.

RLV wouldn't have made sense then given they were unknown and expected flight rate for BLEO missions was too small. Any RLV would've required in orbit refuelling another new technology and probably new engine. That is 3 new things with RLV being very high risk and likely to over budget and schedule. Delays and cost overruns from all 3 would've added up as they needed to be built consecutively. RLV needs engine and in orbit refuelling operational RLV.

[Robotbeat]

Thing is… NASA needs orbital refueling (or at least cryo management) for Artemis and Mars *anyway*. The typical Artemis or Mars reference design makes extensive use of cryogenic propellants, Artemis required refueling as part of the sustaining missions for Artemis HLS.

The smart thing would’ve been to build the architecture around an unflinching embrace of refueling (since it’s needed anyway), and then not start with an RLV at all but with proven EELVs. Develop the RLV(s) on the side in parallel, not on the critical path.

[Coastal Ron]

Back in 2010, they thought SLS would be cheaper and more sustainable.

I don't know who "they" is, but it would be hard for anyone to think that building an "Ares IV" type launcher would be significantly less than the Ares V Congress was cancelling - because it was too expensive.

The reality is that Congress didn't care about cost, otherwise they would have asked NASA to provide a budget estimate and not funded the SLS. Not long after Congress did fund the SLS there was this article talking about development costs for a variety of heavy launchers, including one that is close to what the SLS turned out to be. Here is the article:
https://nasawatch.com/cev-calv-lsam-eds/the-hlv-cost-information-nasa-decided-not-to-give-to-congress/

Congress didn't care to reassess their assumptions, and now most of that development cost is already "water under the bridge" so to speak. But the operational costs and operational limitations of the SLS are still around.

The SLS, and the Orion (which is the only payload the SLS is assigned to carry), can't be the cornerstone of NASA's expansion into space because they 1) cost too much on a Person/$ ratio, and 2) can't support a robust amount of people in space continuously. Sure, they can be used for limited missions, but the U.S. has to decide what it wants for the long term, and then start putting that in place. And the SLS is not part of that.

[TomH]

Back in 2010, they thought SLS would be cheaper and more sustainable.

That is patently not true. No one ever thought that. Senators Hatch, Shelby, Nelson, and Hutchison supported SLS solely for the pork it would bring into their states. They proscribed technical specifications so precise that only obsolete shuttle parts, made in their states, could be utilized in this beast. They then allocated roughly 85% of the funds necessary to develop this albatross at a reasonable pace, so that its development would drag on for many years, allowing even more money in toto to flow into their states as corporate welfare.

As for what NASA should do with it? Cancel it and replace it with this:

[Mr. Scott]

Think the steam locomotives from the 19th century were retired by the 1920s.  So maybe a technology that was useful for a little over a century. 

Goddard invented the rocket around 1912 with some notable history before that point.

We’re about due for a new technology.  But in terms of NASA, the processes they’ve documented only apply to what ‘has’ been built.  It doesn’t apply to new technology.  So you have to retire these processes as well as obsolete technologies.  It is of no benefit to throw billions into steam engine technologies anymore. 

Believe once the ISS is deorbited, this is really where you need to change absolutely everything. 

NASASpaceFlight will only become less interesting as the old NASA programs go offline.  Perhaps some good information in the forums for posterity.