56
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Why does the government still fund SLS while SpaceX is cheaper and has the same capabilities if not better?
It is still way too early to make such a judgement.
It's easy to be overly optimistic about the cost of a program. The Space Shuttle was supposed to have dozens of flights each year and be super-...
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37
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How much of the second SLS has been built?
The Core Stage-2 is currently slated to be delivered in March 2023. It is mostly complete. Core Stage-3 is structurally complete and assembly of the engine section of Core Stage-4 has begun.
The RS-25 ...
- 18k
34
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What is a "Major Component Failure" referred to in news reports about the unsuccessful Space Launch System core stage test firing?
tl;dr
Each engine reports a self-test status to the vehicle it's attached to. "MCF" is one of the possible statuses and indicates that the engine controller has detected a serious - but not ...
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33
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When Artemis runs out of rollbacks
You wrote [bold emphasis mine]:
It was reported that
NASA managers have said the system is rated for two more rollbacks to the VAB, so after this hurricane decision it appears the stack will need to ...
- 18k
30
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Do the solid rocket boosters of the Shuttle and SLS have a self-destruct system and was it activated during the Challenger disaster?
The shuttle stack broke up at ~73 seconds after launch of STS-51L. The Solid Rocket Boosters separated from the other elements and continued flying in a more or less stable manner (surprisingly). ...
- 178k
26
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What is the purpose of the aft skirt on the Space Shuttle and SLS Solid Rocket Boosters?
Main points about the SRB aft skirt are that they:
bear the entire weight of the launch vehicle, prelaunch
had (SLS SRB does not) four hold-down/support posts distributed the loads between the SRB ...
- 9,572
25
votes
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Why won't the SLS boosters be recovered?
The usual answer - $. Booster recovery was only marginally worth it for STS - once you witnessed how every screw and nut was taken apart, cleaned, and reassembled, you began to wonder why not just ...
- 178k
25
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How feasible is a manned flight to Apophis in 2029 using Artemis or Starship?
There's no point in a flyby since there would be no time to conduct any meaningful measurements.
According to Wikipedia, 99942 Apophis will be going about 7 km/s relative to Earth at closest approach ...
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24
votes
Why not crash the ICPS into the Moon?
The upper stage for Apollo 8 through Apollo 12 were sent into heliocentric orbit. On the last five flights, Apollo 13 through Apollo 17, the upper stages were instead intentionally crashed into the ...
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22
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Why isn't the Delta IV Heavy ever used for crewed spaceflight?
What's the reason that they don't use the Delta Heavy for crewed flights to the Moon and beyond?
The Delta IV Heavy isn't powerful enough to send Orion beyond low Earth orbit. Orion masses about 26.5 ...
- 167k
21
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Why can the Falcon 9 be reused while the SLS cannot?
The top-level answer, as others said, is "because it was decided so".
But following that, we have actual design decisions that simply make SLS completely impractical to recover. It focuses on getting ...
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20
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Black/White patterns on SLS boosters, fairings - Are these still roll patterns
These patterns are used for tracking much more than just roll. According to this 2017 article from The Planetary Society, they
will be used by tracking cameras to precisely measure the vehicle's ...
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19
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Will SLS be launched as often as the space shuttle was?
Given the available data, no.
Ignoring details like the lengthy stand-downs after the two loss-of-crew-and-vehicle shuttle mishaps, a naive calculation (135 launches between 4/12/81 and 7/8/11) gives ...
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18
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When Artemis runs out of rollbacks
Partial answer to
What constrains how many rollbacks Artemis can endure?
A big part of it is resonant vibration (due to the crawler) causing fatigue to various and sundry parts of the SLS. You can ...
- 178k
16
votes
What are the differences between SLS and Ares V?
As it turns out, SLS is actually very similar to the original Ares V configuration, proposed around 2002 (I believe). During this time it was known simply as 'CaLV,' or Cargo Launch Vehicle, as a ...
- 1,135
16
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Why were Solid Rockets chosen for the SLS
SRBs have a very high thrust to weight ratio, even if they have an only modest ISP. That makes it complementary with LH2/LOX systems that have a relatively low thrust. Early on acceleration is almost ...
15
votes
Why does the government still fund SLS while SpaceX is cheaper and has the same capabilities if not better?
Eh, to begin with this statement isn't accurate.
SpaceX ... has the same capabilities if not better?
Falcon Heavy as stands can't replace SLS and launch Orion on the required orbit without ...
- 4,111
15
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Will SLS be launched as often as the space shuttle was?
Your question is based on Wikipedia's description of this as "successor to the retired Space Shuttle". This statement is so severely flawed as to be basically untrue.
The Shuttle was ...
- 1,940
14
votes
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Does the SLS mobile launch platform share any hardware with STS or even Saturn I/V MLP?
The two-story gray platforms at the base were originally built for Apollo, modded for shuttle, and now modded again for SLS.
The towers are new and suffered a lot of cost and schedule issues. Most of ...
- 178k
13
votes
Why doesn't NASA plan a manned Venus flyby first?
A Venus flyby does little to nothing towards the stated goal: a manned landing on Mars.
because you get a lot closer to the Sun than on a Mars mission, you need to modify the spacecraft to reject ...
- 126k
13
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Why does the government still fund SLS while SpaceX is cheaper and has the same capabilities if not better?
All the answers are right in their own way. One thing that is not addressed:
The Falcon Heavy is not even remotly on par with the SLS in terms of rocket diameter and payload mass.
According to ...
- 546
13
votes
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What do the banana values mean in this tweeted plot of heavy lift vehicle capabilities?
For most of the vehicles there seems to be a correlation between size and "banana number", which is not yet a SI-recognized unit of measure (And I really hope they don't decide to keep a ...
- 14.9k
13
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How can Artemis 1 take so much longer for Earth-Lunar transit than the Apollo missions did?
The goal of the Apollo missions was to land humans on the Moon and return them to Earth. That requires a surprisingly large delta-V capability. (In terms of delta-V, is easier to land a vehicle on ...
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12
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What makes SLS (Space Launch System) \$10 Billion (or \$36 Billion) project?
Pork. It is a jobs program not a technology program.
The SRB's are built by ATK, but the design ensured they needed to be reworked, so they could not just the existing Shuttle ones. Need an extra ...
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12
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Why will SLS Block I bring less mass to LEO than the STS shuttle system did?
It's always difficult to make apples-to-apples comparisons between the space shuttle and other launchers, because the orbiter is ambiguously part launcher and part payload. This is compounded by the ...
- 167k
12
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What is the status of the F-1B engine development?
That project has been cancelled (or at least put on hold) as of June 2019.
But NASA discontinued studies of upgrading the SLS, including study of
reviving the F-1. Soon the testing of the F-1 gas ...
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12
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Why does the government still fund SLS while SpaceX is cheaper and has the same capabilities if not better?
Part of it is leveling employment. The government is fond of large projects that require multi-year ramp-up and ramp-down and massive up/down swings in employment need.
Suppose in 2019 you're hiring ...
11
votes
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Can the SLS reuse its solid rocket boosters?
It can but it won't.
It was decided that the costs of recovery, inspection and refurbishing the boosters plus increased risk of disaster due to unnoticed wear is just not worth it - the boosters will ...
- 54.9k
11
votes
Could the solid boosters of SLS be replaced by reusable Falcon 9 first stages?
The SRBs for the Shuttle and SLS are used to get the stack moving and off the pad, so that the more efficient LOX/LH2 engines can do the hard work.
In the case of the Space Shuttle, an amazing ...
- 79.4k
11
votes
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What does the software quality process for NASA's SLS look like?
I have retrieved via FOIA request the "Space Launch System Program (SLSP), Flight Software Application, Software Assurance Plan (SAP)". It is the core document describing the software development ...
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Only top scored, non community-wiki answers of a minimum length are eligible