50 votes

What is "mission design"? What do mission designers do (if such a designation exists)?

Yes, there are people whose sole job is "mission design." They design the trajectory that a spacecraft should follow to fulfill its mission and all of the maneuvers needed for that to happen....
ChrisR's user avatar
  • 6,220
30 votes

Refueling a Mars mission on the way

Unfortunately sending propellant ahead to pick up on route will not help. The same amount of propellant will be needed regardless if both are accelerated together or separately. Also if launched ...
Slarty's user avatar
  • 9,323
26 votes

How hard is it to fly through the tail of a comet? Has it been done?

Ulysses, the shuttle-launched joint NASA/ESA probe to study the sun's polar regions, ran through three comet tails, more or less by chance. Ulysses Catches Record for Catching Comets by Their Tails ....
Organic Marble's user avatar
25 votes

Are there any studies about "ping pong" cyclers between gas giants?

In a sense, this "ping pong" is what cycler orbits attempt to do, you are just overestimating the power of flybys. To make the distance between Jupiter and Saturn in just 4 years (one way?), ...
SE - stop firing the good guys's user avatar
20 votes
Accepted

How to choose the best direction to leave Earth's sphere of influence?

Your intuition is quite correct. The Hohmann transfer orbit is a bi-tangential orbit, so at the point where the spacecraft leaves Earth, it is travelling in parallel to us. In the case of Mars, we ...
SE - stop firing the good guys's user avatar
19 votes

Refueling a Mars mission on the way

If you think less about fuel and more about the other amenities for a long distance mission, you are awfully close to the concept of a cycler. The basic idea is that you take a big vessel, on which ...
mlk's user avatar
  • 449
17 votes

Refueling a Mars mission on the way

The real problem is that, in space travel, your speed determines your trajectory, and therefore two objects can't follow the same trajectory at different velocities. Precisely, a faster interplanetary ...
armand's user avatar
  • 559
15 votes

How hard is it to fly through the tail of a comet? Has it been done?

Rosetta collected dust from 67P/Churyumov-Gerasimenko and analyzed it under an atomic force microscope, without landing on the cometary body itself; depending on your definitions this would seem to ...
Russell Borogove's user avatar
15 votes
Accepted

Could Falcon 9 push the second stage a little longer after MECO and before separation?

After the first stage engines are shut down, the only way for the second stage to extract energy from the first stage is to push away from it, which is how the separation already works. Attempting to ...
Erin Anne's user avatar
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14 votes
Accepted

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 ...
David Hammen's user avatar
  • 74.8k
12 votes
Accepted

Did UAE's Al-Amal (Hope) Emirates Mars Mission (EMM) launch directly into an interplanetary trajectory or did it spend some time in LEO?

What was the duration of the launch window this day? According to Spacelaunchnow, the daily launch window was instantaneous, but there were daily opportunities from July 15 to August 12. Did it ...
Russell Borogove's user avatar
12 votes
Accepted

Why did Pioneer 11 use a gravitational assist to swing above the ecliptic plane... twice?

According to NASA's history on the mission, Pioneer 11's goals included both investigation of the solar wind outside of the ecliptic, and a look at the polar regions of Jupiter, which appeared to have ...
Russell Borogove's user avatar
12 votes

How hard is it to fly through the tail of a comet? Has it been done?

The two Vega probes comes to mind, ending their implausible sounding mission of slipping balloons into the atmosphere of Venus with a flyby of Halley's comet in 1986. They took a heavy beating flying ...
SE - stop firing the good guys's user avatar
12 votes

What is "mission design"? What do mission designers do (if such a designation exists)?

For the shuttle program this work was called "flight design". Acronymology: DM - Organization code for Flight Design and Dynamics Division GPC - General Purpose Computer ISS - ...
Organic Marble's user avatar
11 votes

What is "mission design"? What do mission designers do (if such a designation exists)?

I think this term varies by organisation. In my expereience it is a multidisciplinary topic. Whilst a key part of mission analysis is how to get to and around the orbit, as large an effort has to be ...
Puffin's user avatar
  • 9,524
10 votes

How hard is it to fly through the tail of a comet? Has it been done?

The International Cometary Explorer spacecraft passed through the plasma tail of 21P/Giacobini–Zinner in September, 1985, which I think was the first time the human race had engineered such a ...
MadHatter's user avatar
  • 201
9 votes

How many burns does New Shepard have during a descent?

Only one burn, just before landing, according to Blue Origin's broadcast of NS-12's flight. The only events during climb relating to engines are liftoff and MECO (main engine cut off). After apogee, ...
Camille Goudeseune's user avatar
9 votes

How can Artemis 1 take so much longer for Earth-Lunar transit than the Apollo missions did?

Apollo burned a lot of fuel in exchange for a quicker mission. Back in the 60's the spacecraft had a very short lifespan, mostly limited by the capacity of the batteries. Nowadays battery capacity is ...
Innovine's user avatar
  • 4,625
9 votes

Could Falcon 9 push the second stage a little longer after MECO and before separation?

Look at it a different way. If the two stages separated in a non-violent manner - i.e., one didn't "push" away from the other - then they would continue side by side (or end to end) as ...
manassehkatz-Moving 2 Codidact's user avatar
8 votes
Accepted

Will the Parker probe use aerobraking at Venus? If not, why not?

It's using the gravity of Venus alone. Skimming the atmosphere would risk damaging the spacecraft From the NASA blog On Oct. 3, Parker Solar Probe successfully completed its flyby of Venus at a ...
Machavity's user avatar
  • 7,905
8 votes
Accepted

How many burns does New Shepard have during a descent?

The Falcon 9 first stage is making three burns wile descending: Nope. It is making two burns while descending. boostback burn This burn happens while the rocket is still ascending. This burn only ...
Jörg W Mittag's user avatar
8 votes
Accepted

Why is the gas giant grand tour interval 175 years when the synodic period of Uranus and Neptune is 171 years?

A couple considerations enter here. We do not expect the alignments to occur every 175 years over the long haul. Rather, they are likely to occur in clusters internally spaced by that interval until ...
Oscar Lanzi's user avatar
  • 8,505
7 votes

Refueling a Mars mission on the way

Rather than having fuel tanks you meet on the way the better way would be preposition fuel tankers at the start and end of the trip i.e Earth and Mars orbit. You put fuel tankers in Earth's orbit as ...
Rob's user avatar
  • 200
6 votes

Powered Explicit Guidance - Why wouldn't it be used?

Shuttle used open-loop guidance (pre-programmed table of pitch / yaw / roll) for first stage, switching to PEG at SRB sep. This was to avoid exceeding first stage dynamic pressure/structural limits ...
Organic Marble's user avatar
5 votes

Which deorbit trajectory minimizes reentry heating?

@ChristopherJamesHuff is right, many assumptions need to be made to make this feasible, but assuming a ballistic Crew Dragon entry from a 400 km circular orbit is enough to demonstrate some important ...
BrendanLuke15's user avatar
5 votes
Accepted

Where did the Herschel Space Telescope go in 2013?

The telescope was placed into a heliocentric orbit when its helium supply was depleted On 29 April 2013, ESA announced that Herschel's supply of liquid helium, used to cool the instruments and ...
Machavity's user avatar
  • 7,905
5 votes
Accepted

Why does targeting in the VNB frame lead to a different maneuver magnitude than targeting in an inertial frame?

It's not about the frames; you just haven't fully constrained the orbit that results from the burn. I was able to get the DVs to match using your script by just adding an inclination constraint. The ...
Matt B's user avatar
  • 741
5 votes

Powered Explicit Guidance - Why wouldn't it be used?

The Powered Explicit Guidance is a successful algorithm with many practical applications. However, there are areas of improvement that can be made. As can be seen, there are many approximations made ...
ChrisR's user avatar
  • 6,220
5 votes

if there are any advantages of time regularization such as Sundman transformation in gravity-assisted trajectory optimization?

What are the real advantages of time regularization? The key advantage of time regularization applies to eccentric orbits and using a fixed step size integrator. The issue is that there's always a ...
David Hammen's user avatar
  • 74.8k
4 votes

Refueling a Mars mission on the way

As in the other answers, your ideas won't save fuel and time, but they may in the future vastly improve likelihood of mission success and crew safety, at the cost of more fuel and time. An unpeopled ...
Selene Routley's user avatar

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