Hot answers tagged

47 votes

Why didn't Voyager 1 and Voyager 2 crash on into Jupiter or Uranus when they approached near to these massive planets?

why weren't they completely attracted by their gravitational field? How much a trajectory is changed, depends on 3 factors: the mass of the planet, the speed of the spacecraft, the distance between ...
Hobbes's user avatar
  • 127k
28 votes

Optimal depth for underground flyby?

The Optimal Depth is Precisely (Almost) No Depth I solved this problem using a numerical differential equation solver to investigate a range of flyby approach angles. The results are fascinating! I ...
A McKelvy's user avatar
  • 2,482
22 votes
Accepted

What happened to Mariner 2 after it flew by Venus?

After the close encounter with Venus on December 14, 1962, the last radio contact was on January 3, 1963. No tracking can be done after that as the spacecraft is too small and too far away. The ...
SE - stop firing the good guys's user avatar
21 votes

Why didn't Voyager 1 and Voyager 2 crash on into Jupiter or Uranus when they approached near to these massive planets?

To add to the answers @Hobbes & @Steve Linton posted, the mission designers indeed knew Jupiter's gravity field quite well from the orbits of Jupiter's moons. But before the Voyagers arrived they ...
Tom Spilker's user avatar
  • 18.3k
18 votes
Accepted

How is JunoCam different from a normal CCD camera?

JunoCam used different technologies than does the typical framing camera one buys at a store. A typical digital color camera uses a Bayer filter pattern, a row of alternating tiny blue and green ...
David Hammen's user avatar
  • 73.8k
18 votes
Accepted

Will crewed vehicles ever follow multi-flyby trajectories?

Given the mass costs in terms of consumables and the risk and support costs of keeping humans in space for longer, it seems unlikely that the multiple Earth-Venus flybys used by a lot of robot probes ...
Steve Linton's user avatar
  • 19.6k
16 votes
Accepted

Is the Flyby Anomaly still a thing?

Yes, the Flyby Anomaly is still an unsolved problem. Studies have found several candidates for the cause of the anomaly. A recent study examined Juno's behavior on its Jupiter orbits, and found the ...
Hobbes's user avatar
  • 127k
16 votes

What time will news from New Horizons' Arrokoth (2014 MU69) encounter become available to the public?

In simple explanation, we won't able to know what's up with New Horizons right away. The probe will be busy collecting all the science data during the high-speed flyby. Closest approach will be at ...
not_Prince's user avatar
  • 1,537
15 votes

Why didn't Voyager 1 and Voyager 2 crash on into Jupiter or Uranus when they approached near to these massive planets?

Let's try and understand how gravity works in space. This is kind of key idea to understanding lots of issues in space travel and astronomy. So imagine a space probe, or rock, which is heading in ...
Steve Linton's user avatar
  • 19.6k
15 votes
Accepted

Will Dragonfly flyby Jupiter en route to Saturn?

Here is a paper which among other things includes the results of a trajectory search. They say Gravity assists of Earth, Venus, and Mars were included with a patched conics assumption. Jupiter was ...
Steve Linton's user avatar
  • 19.6k
13 votes
Accepted

Optimal depth for underground flyby?

Assuming a uniform planet with radius $1$ and gravitational parameter $1$, if $V_\infty$ is the speed at infinity and $r$ is the closest approach to the center, then the maximal speed is $V_m = \sqrt{...
Litho's user avatar
  • 2,040
12 votes

What are the gravitational assist effects on the inclination of a probe's trajectory, from passing by Jupiter at different latitudes?

Yes, Jupiter can make a trajectory perpendicular to the ecliptic, which is exactly what it did for Ulysses, which observed the poles of the Sun: The function is just vector addition. It depends on ...
Mark Adler's user avatar
  • 58.1k
10 votes
Accepted

Why would Cassini need to reach 64 degrees inclination before "threading the needle"?

This is purely a speculation, as I have not found any official sources to confirm it, but I think they want to be able to view Saturn's pole during the fly by. The trigonometry works out at least: If ...
SE - stop firing the good guys's user avatar
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
  • 9,976
9 votes

Optimal depth for underground flyby?

Adding my own numerical time-step simulations here. The effect seems to be quite subtle, only increasing the deflection angle by a fraction of a degree at shallow depth. For a unit mass, with unit ...
SE - stop firing the good guys's user avatar
7 votes
Accepted

What angular resolution is expected during New Horizon's flyby of Ultima Thule?

Update 2019-01-01: I've calculated detailed resolution and range values for the encounter's imaging schedule. The chart can be found in this answer (scroll down to Resolution during capture in meters ...
Alex Hajnal's user avatar
  • 1,971
7 votes
Accepted

Delta-v obtained from Titan by the Cassini spacecraft; just how much of a "gas tank" was it?

I downloaded the ~170 SPK reconstructed trajectory kernels (at Saturn) from the NAIF node of PDS and searched for instances where Cassini was within Titan's sphere of influence (~43,000 km). Note that ...
BrendanLuke15's user avatar
7 votes
Accepted

Flyby puzzler; starting from Earth, how many times can you use Jupiter flybys in one century?

As always with such puzzlers, one need to find something to exploit heavily :) Usually when constructing multi-flyby trajectories ("ball of yarn"), one relies on keeping a consistent semi-...
SE - stop firing the good guys's user avatar
6 votes
Accepted

What is the closest fly-by of a planet/moon ever completed?

Here's a list of what the closest flybys that I have found of several objects. For Cassini and Galileo, I took the closest approaches they had to any object, pre-impact. Earth: Galileo- 301 km Moon- ...
PearsonArtPhoto's user avatar
  • 121k
6 votes
Accepted

How close to the moon would a flyby trip likely attempt?

SpaceX has posted a nice info graphic: The perilune (closest approach to the moon, number 06 in the graphic) is going to be about 125 miles / 201 km.
DarkDust's user avatar
  • 12.5k
6 votes

Why didn't Voyager 1 and Voyager 2 crash on into Jupiter or Uranus when they approached near to these massive planets?

Let's focus on the "why weren't they completely attracted by their gravitational field" question here. You've probably seen Newton's cannonball diagram before: In this diagram, the distance from the ...
jcaron's user avatar
  • 965
6 votes
Accepted

Does JPL's Horizons have better MU69 state vectors for the New Horizons flyby somewhere?

Thanks to Jon. D. Giorgini at NASA JPL for pointing out that there is indeed a much newer solution in Horizons. The trick is to use the newer, though unofficial designation Ultima Thule when ...
uhoh's user avatar
  • 149k
6 votes
Accepted

Would it be practical to fly a probe to Mars using gravitational assistance from Venus?

It is not practical to use Venus to get to Mars in all but one circumstance. I searched for Earth-Mars and Earth-Venus-Mars (EVM) trajectories in a 900 day launch period starting Jan. 1st 2024. The ...
BrendanLuke15's user avatar
5 votes
Accepted

How to calculate New Horizons' MVIC camera max resolution at Pluto and Ultima Thule?

A good sanity check is to compare your results with what the New Horizons team is reporting. It is also useful to consider whether there are any other factors at play that could throw the numbers off....
Alex Hajnal's user avatar
  • 1,971
5 votes
Accepted

What time will news from New Horizons' Arrokoth (2014 MU69) encounter become available to the public?

According to this article, "The first images are expected by the evening of January 1, with release planned for January 2. More, higher resolution shots should follow." Evening is presumably that of ...
Alex Hajnal's user avatar
  • 1,971
5 votes

Why didn't Voyager 1 and Voyager 2 crash on into Jupiter or Uranus when they approached near to these massive planets?

At the heart of this question is how the gravity assist 'works', at least an intuitive understanding of it. When a space probe uses gravity assist from a planet, it gets some energy from it, which (...
Neil_UK's user avatar
  • 271
5 votes

Which deep-space spacecraft flew closest by Earth during a gravitational assist?

Wikipedia - List of earth's flybys states that 301km by Galileo is the shortest flyby. However it has contradicting information, and seems to be false: gravity assist en route to Jupiter; minimum ...
DialFrost's user avatar
  • 1,673
5 votes
Accepted

Is there a parameter that describes the angle between the spacecraft's position and the sun angle or direction of the Earth's motion?

This question has some really good answers that explain gravity assists and how they could be conceived. If you're setting up a simulation, this report probably has everything you need, theory, ...
pathfinder_EOS's user avatar
4 votes

Why didn't Voyager 1 and Voyager 2 crash on into Jupiter or Uranus when they approached near to these massive planets?

Newton discovered gravity (and invented mathematical laws to describe it) a long time before Pioneer 10 flew! It has been possible to calculate the mass of the planets with a fair degree of accuracy ...
Ed999's user avatar
  • 141
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
  • 58.1k

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