# Questions tagged [sls]

Space Launch System, the putative replacement for the Space Shuttle for future large missions.

58 questions
Filter by
Sorted by
Tagged with
152 views

### Why is ESA developing the Vinci engine rather than buying RL10Bs?

The Vinci engine seems very very similar to the RL10B. Both are hydrolox expander-cycle engines with 465 s Isp and extendible nozzles with a ~250:1 expansion ratio. The biggest difference is that the ...
144 views

### What are these wires on the side of the SLS core stage?

I was reading about the SLS core being moved for testing and I noticed something odd on the core stage. There's several lines on the stage, which in closer inspection are wires. It's not obvious what ...
174 views

### Where are the lost RS-25D Block 2 engines?

There were 21 RS-25D Block 2 engines made. Two of them never flew. Three of them were lost with the Columbia disaster. 16 of them are tagged for SLS's use, including 14 previously flown, and the two ...
147 views

### Did the shuttle SRBs have separation motors?

Looking at a NASA fact sheet about the SLS SRBs and I noticed it has at the bottom around the nozzle, separation motors. Watching shuttle launches It looks to me like the SRBs continue to fire ...
869 views

79 views

### Could the SSMEs of the SLS do retro burns?

The SLS will use the main engines of the space shuttle. Are these capable of retro-burns in the upper atmosphere like SpaceX’s Merlin engines? More broadly, could the SLS’ main engines and ...
98 views

### How does the economy of a direct launch (to the Moon) compare with two launches docking in orbit?

How much more efficient would it be to use a launcher big enough to go directly to the surface of the Moon like Apollo did, compared with using two launches with a lesser rocket, say one with the ...
77 views

### Are the APUs on the SLS SRBs planned to be hydrazine powered?

I recently read that the Space Launch System core stage, which uses renamed / slightly reworked Space Shuttle Main Engines and therefore requires a hydraulic system to service said engines, will use ...
331 views

### Why doesn't NASA plan a manned Venus flyby first? [closed]

After America will have returned to the Moon, why won't NASA make a Venus flyby mission with the Orion/SLS before going on to manned flights to Mars? They are planning crewed missions to Venus (...
875 views

### What exactly is a “Green Run test” for SLS that NASA is considering skipping?

The Ars Technica article Rocket Report: A new Delta 2, Blue Origin inks with NASA, a fiery Falcon Heavy says: Boeing seeks to ship SLS core stage by the end of 2019. With a renewed emphasis from ...
137 views

### What is holding SLS back from launching?

I'm kind of confused on this point SLS has engines, a tank, side rocket boosters, a capsule, and seemingly all of the pieces. What is the major technical issue right now that is keeping SLS from ...
167 views

### Why would an 8-minute burn result in a 6-month delay?

The Ars Technica article Vice President may tell NASA to accelerate lunar landings ends with: And on Thursday, NASASpaceFlight.com reported that the agency is considering skipping a critical test ...
107 views

### Can Delta Heavy launch a fully fueled upper stage with no payload attached?

There is right now talk of a potential dual launch mission to fulfill EM-1, where a Delta Heavy would launch a fully fueled upper stage to LEO, to there bet met with the Orion spacecraft, likely ...
1k views

### NASA's RS-25 Engines shut down time

As a follow up to my other question about RS-25's ramp-up time, I was wondering what would be the ramp-down times for the RS-25, i.e. what would be the time that takes to go from 100% thrust to 0% ...
246 views

### NASA's RS-25 Engines

I am developing a FSX-based space flight simulator FSX SpacePort. I've been trying to get the detailed specs on NASA's RS-25 engine, namely, what were the ramp-up times for this engine? As in, how ...
238 views

### Could the SLS reach orbit without solid rocket boosters?

Could the SLS block 1 reach orbit without solid rocket boosters, and if so, how much payload could it lift? If it couldn't reach orbit in the block 1 config, could it do so with the Exploration ...
479 views

### What are these discs on the Crawler-Transporter?

I've just watched this footage of SLS's Mobile Launcher Platform being rolled out to LC-39B for fitting tests. On the front of the drive trucks are two rotating discs with red markings which are ...
121 views

### What is the nature of the sextant tests on the ISS for Orion cis-lunar emergency navigation?

According to the NASA Johnson video Space to Ground: A Star to Steer By: 08/10/2018: A tool that once helped sailors cross vast oceans for centuries is now being put to the test in space. The crew ...
84 views

### What is the scheduled launch date history for SLS EM-1?

The Falcon Heavy was famous for being "6 months away" for around 6 years, seen in this chart. How has the SLS maiden launch schedule changed since its first proposed date? P.S. If someone could ...
5k views

### Do the solid rocket boosters of the Shuttle and SLS have a self-destruct system and was it activated during the Challenger disaster?

Videos of the Challenger shuttle explosion show both solid boosters speeding on after the main tank detonated. Were they eventually self-destructed by the ground control, or why not, and why not ...
266 views

### How much will Europa Clipper weigh?

I realize that NASA will have to change Europa Clipper's loadout based on whether they are launching on the SLS 1b or the Atlas 5 backup, but does anyone know what those two mission masses will be, ...
493 views

### RS-25 Hot Fire Test

Yesterday, NASA Stennis successfully completed a hot fire test of Aerojet Rocketdyne RS-25 a.k.a SSME. It was noted in the webcast before the test started that they were testing the 'engine controller'...
880 views

### What does the software quality process for NASA's SLS look like?

What does the software quality process for NASA's SLS look like? What are the relevant standards that they have to comply to? Do they have to show that they are CMMI compliant, for example? I'm ...
345 views

### Do Orion's solar panels have adjustable sweep?

In this video overview of NASA's proposed EM-1 mission, the solar panels on the Orion spacecraft are initially shown extending perpendicular to the spacecraft (at around 3:46). Shortly after that, as ...
383 views

### Were any Components Off The Shelf (COTS) used in the Space Shuttle?

Are there examples of Components Off The Shelf (COTS) used in the Space Transportation System? And is NASA considering using COTS in future manned space flight systems like Orion and the SLS?
621 views

### Why will SLS Block I bring less mass to LEO than the STS shuttle system did?

The Space Transportation System (STS) could bring a fully loaded shuttle orbiter of 109 tons to orbit (or maybe empty+payload 68+25=93 tons). The Space Launch System (SLS) Block I is based on STS, but ...
748 views

### How does Exploration Mission 1 orbit differ from Apollo-era free-return? How far from Earth (and Moon) does it go?

I'm having trouble understanding the current orbit planned for NASA's Space Launch System's Exploration Mission 1. Is it possible to explain how the planned orbit works and what the maximum distance ...
618 views

### How are SLS SRBs considered man-rated?

Using solid rocket boosters on a manned launch comes with some additional risks because they can't be turned off or throttled down once lit. For the Shuttle this created some additional failures modes ...
167 views

### What naturally occurring navigational information is available for an autonomous return of SLS's EM-1?

This answer details some of the requirements that would need to be met if the Space Launch System's planned Exploration Mission 1 were to be human rated. I've further trimmed that truncated selection ...
169 views

### Human Rate the ICPS on EM-1 of SLS

What specifically must be done to Human Rate the Interim Cryogenic Propulsion Stage (ICPS) to fly humans on Exploration Mission 1 of SLS?
258 views

### Can SLS use subcooled LOX?

The SpaceX Falcon 9 FT is using subcooled liquid oxygen. I understand that LOX gets significantly denser at lower temperatures so more propellant can be filled in the rocket's tank. Can NASA SLS RS-...
1k views

### Why did NASA design the SLS do the job of both the Ares I and Ares V?

The design of the Constellation program called for two main launch vehicles, The Ares I and the Ares V. The Ares I was said to be human-rated and was to be used to carry the Orion vehicle and its crew ...
5k views

### What are the differences between SLS and Ares V?

SLS is to a large degree a continuation of the canceled Ares V, basically the STS without the orbiter. But what changes in design were made from Ares V to SLS? What were the reasons for those changes? ...
3k views

### Could the solid boosters of SLS be replaced by reusable Falcon 9 first stages?

Is it feasible to redesign the Space Launch System to use a pair of reusable Falcon 9 first stages instead of the five-segment solid boosters now being developed? The reason would be to lower launch ...
194 views

### Are rocket boosters insulated?

Reading about NASA testing the SLS (Space Launch System) booster and they are chilling it to 40 degrees Fahrenheit. This confused me because they are going to fill it with liquid oxygen and liquid ...
403 views

### Which are the benefits and challenges for a new SLS rocket version with four SRB? [closed]

Which are the benefits and the challenges for a new Space Launch System (SLS) version with four Solid Rocket Boosters (SRB)? Benefits i mean what would gain in payload capabilities, how much more ...
2k views

### Why won't the SLS boosters be recovered?

The SLS will be using five segment boosters derived from the four segment ones used during the STS program. Almost all of the STS boosters were recovered and reused, however NASA doesn't plan to ...
552 views