Skip to main content
25 votes
Accepted

In deep space missions, how much of the journey is pre-programmed and how much is "direct" control?

The journey to the destination is about always completely pre-planned. All the gravity assists, close fly-bys, and so on, are planned before launch - and often long before the probe design is ...
SF.'s user avatar
  • 55k
18 votes

Why are Europe’s Air & Space Academy and DLR urging ESA and CNES to reconsider the use of solid fuels for the proposed Ariane 6?

This is a pretty interesting question in retrospect now. When it was asked in 2013, booster re-usablity was just a gleam in SpaceX's eye. The first Falcon 9 attempt to land a booster wasn't until ...
SafeFastExpressive's user avatar
18 votes
Accepted

JWST - image acquisition - what is a dither pattern?

Generally, In astrophotography, to dither means to shift the pointing of the telescope slightly in random directions between exposures. This allows hot and cold pixels, cosmic ray artifacts, and ...
Camille Goudeseune's user avatar
15 votes
Accepted

Were any other Space Shuttles ever planned?

I think Sagan was being optimistic. The original plan was for a large fleet of shuttles to support a very high mission flight rate, but according to Wikipedia, by 1983, the plan was to hold the fleet ...
Russell Borogove's user avatar
14 votes
Accepted

Any potential downside to throwing personal life support out the door on the Moon?

They threw out the PLSS, but that didn't leave them without the use of those space suits entirely. The space suits could be coupled via umbilicals to the LEM ECLSS or to the CM life support system (...
Hobbes's user avatar
  • 128k
14 votes
Accepted

Is there any independent evaluation/report on the feasibility of SpaceX going to Mars by 2024?

I don't have any independent evaluations on hand but it is almost completely certain that SpaceX will not have any rockets landing on Mars in 2024 or leaving for Mars in 2024. Launch windows aren't ...
Dragongeek's user avatar
  • 19.2k
13 votes

Have there been any setbacks due to COVID-19-- like delays or data-loss?

Definitely. There's an article in Spektrum.de on it. It's in German, but it references some English-language articles. A referenced article (English) says that launches at the Guiana Space Center (...
Greg's user avatar
  • 4,287
10 votes
Accepted

How would a Jupiter flyby have helped to get to the Sun? Why was it later ruled out?

A gravity assist at Jupiter would have been used to decrease Solar Probe (Plus)'s orbital speed, lowering its perihelion as explained well in this answer. Credit: NASA/JHUAPL In fact, for such an ...
Jack's user avatar
  • 9,966
9 votes

Before the Columbia accident, were there shuttle manifests/plans for after ISS assembly complete?

In case anyone else is curious, I did find some information on this, in a document dated Jan 29, 2003, three days before the Columbia accident. It shows projected flights going out to STS-147 in late ...
Organic Marble's user avatar
9 votes
Accepted

What was back-up plan in case of Apollo CSM Primary Guidance System IMU went to gimbal lock?

The Apollo attitude control system starts from a known orientation established by taking star sightings, then uses gyroscopes to track the change in orientation over time. The problem with gimbal lock ...
Russell Borogove's user avatar
7 votes

Why didn't NASA re-use more astronaut crew members?

I'm writing this answer as a community wiki. The reasons are manyfold; feel free to add more. @Digger notes that NASA requires Commanders to have previous experience in space. It is therefore ...
6 votes

Have there been any setbacks due to COVID-19-- like delays or data-loss?

Let the bad times roll! :-( NPR reports that the Russian-European ExoMars mission to Mars has been delayed. While factors other than COVID-19 figured into this decision, there was also this ...
Oscar Lanzi's user avatar
  • 8,525
6 votes
Accepted

Where is Lucy going? (asteroid mission)

A more detailed trajectory is available in the usual place for the sort of detail you're looking for: the NTRS. LUCY: NAVIGATING A JUPITER TROJAN TOUR A unique trajectory was discovered which visits ...
Hobbes's user avatar
  • 128k
5 votes

How (the heck) can 2014 MU69's orbit be know well enough for a close flyby by New Horizons?

Okay, collecting my comments into an answer: As soon as you have a visual, and have enough delta-V, you CAN get a fly-by, although precise time and speed of flyby will remain unknown until much ...
SF.'s user avatar
  • 55k
5 votes
Accepted

How (the heck) can 2014 MU69's orbit be know well enough for a close flyby by New Horizons?

The long orbital calculations of Pluto's orbit were done primarily to save fuel, and secondarily to target a very narrow region. The mission intended to fly between the Sun and Pluto and Charon (And ...
PearsonArtPhoto's user avatar
  • 121k
5 votes
Accepted

How fast are trips to the Moon for unmanned spacecraft typically?

Are most trips to the Moon actually around 3 or 4 days, and not the 5.0 days of a half-ellipse? The 5 spacecraft of the US Lunar Orbiter program took 3.8-3.9 days to reach lunar orbit. The Ranger ...
Russell Borogove's user avatar
5 votes
Accepted

How did NASA decide on its missions?

It depends on the type of mission. Generally: Scientific missions these days are decided on via the decadal surveys (for astronomy, planetary science and earth science). These are organized by the ...
Hobbes's user avatar
  • 128k
5 votes

Has space weather ever impacted spacecraft launch schedules?

In 2014 a solar flare delayed the launch of a private cargo delivery to the International Space Station by 24 hours due to concerns over space radiation. The event occurred as the commercial ...
Fred's user avatar
  • 13.1k
5 votes
Accepted

Why is 90 sols a standard mission duration for robotic spacecraft on the surface of Mars?

I believe I might have found an answer to this question in this interesting paper, which reviews the origin of duration and distance requirements for planetary mobility systems. It appears the 90 sol ...
Armadillo's user avatar
  • 1,426
4 votes

Were there contemporary criticisms of NASA's pre-Challenger plans to exclusively use the Shuttle for US launches?

According to The Space Shuttle Decision, the White House Office of Management & Budget, at the end of 1971, had concerns: Similarly, the OMB would not permit its shuttle to be all things to ...
Russell Borogove's user avatar
4 votes

Assuming MLM/Nauka is launched, what happens to MRM-1/Rassvet?

Actually, the idea of MLM being docked to the bottom of Zarya FGB was a thing in the years 2004-2007. At that time MRM-1 Rassvet and MRM-2 Poisk didn't exist, and DC-1 Pirs was supposed to move to the ...
ISS_fan14's user avatar
4 votes
Accepted

Assuming MLM/Nauka is launched, what happens to MRM-1/Rassvet?

The MLM is replacing the DC-1 docking compartment (Pirs). Not Rassvet. It is docking to Zvezda not Zarya. Russian Space Web has an excellent article on the history of the MLM/Nauka/FGB-II module. ...
geoffc's user avatar
  • 79.8k
4 votes

How would a Jupiter flyby have helped to get to the Sun? Why was it later ruled out?

The Jupiter flyby mission concepts were nuclear-powered. They were told to come up with a non-nuclear option.
Mark Adler's user avatar
  • 58.2k
4 votes

How much time does the ISS require in "non value adding activities"?

The NASA ISS payload utilization (science experiments) for FY 2019 was 967 hours, according to the ISS National Laboratory. EDIT: My previous conclusion seemed low on the payloads utilization numbers. ...
Doresoom's user avatar
  • 1,754
3 votes

Where can I find detailed information on spacewalks?

Most of the publicly available procedural information you seek is on the Johnson Space Center Flight Data File page. It may help to briefly review the organization of the EVA checklist documentation. ...
Organic Marble's user avatar
3 votes

What are the limiting factors for interplanetary mission trajectories?

There's plenty of additional constraints on interplanetary trajectories. Of course the ones you mentioned first are the most driving constraints. Concerning the others you mentioned maximum number ...
Alexander Vandenberghe's user avatar
3 votes
Accepted

How well can the orbits of Jupiter Trojans to be visited by Lucy be predicted?

In this answer to the question How to calculate the planets and moons beyond Newtons's gravitational force? I show that you can calculate the Sun, the Moon, the planets and several asteroids to one ...
uhoh's user avatar
  • 149k
3 votes

Why does ExoMars have more landing ellipse flexibility in 2020 than in 2018?

My answer is based on the article: "Selecting a Landing Site for the ExoMars 2018 Mission". Vago, J.L., Lorenzoni, L., Calantropio, F. et al. Sol Syst Res (2015) 49: 538. https://doi.org/10.1134/...
Eviatar.E's user avatar
  • 958
3 votes
Accepted

Most likely future sample return missions?

One mission planned for launch inv2024 is the Japanese Martian Moons EXploration. MMX will land on Phobos to collect and return samples, as well as flying by Deimos and studying the Martian climate.
Oscar Lanzi's user avatar
  • 8,525
3 votes

How was each Space Shuttle contingency rescue missions numbered?

After STS-115, the rescue mission designations were based on the corresponding regular mission that would be replaced should the rescue mission be needed. Wikipedia Here's an example of how that ...
Organic Marble's user avatar

Only top scored, non community-wiki answers of a minimum length are eligible