78

New Horizons will never overtake Voyager 1. Although New Horizons is currently faster than any other man-made object, it won't be by the time it reaches the outer corners of the solar system. From the John Hopkins University/Applied Physics Laboratory New Horizons page: Though New Horizons will also reach 100 AU, it will never pass Voyager 1, because ...


51

The process was a great deal more sophisticated than pointing and thrusting, and the CSM was cooking along at over 1600 m/s, circling the moon every 2 hours. Mission control, however, had fairly precise tracking of the positions of both the CSM and the landing site, and they computed the correct time of launch to begin the rendezvous using powerful Earth-...


46

Here's a nice graph of Voyager 2's speed, and the difference made by the gravitational assists: You can see that the probe slowed down between assists. New Horizons would follow a similar graph, but with fewer assists its speed will end up below Voyager 2's, as @gerrit said.


33

The Lunar Roving Vehicle did have a (form of) compass. It was gyroscopic rather than magnetic, thus it needed calibration when first powered up using the sun angle as a reference. It's in the upper left of the console here: According to Wikipedia: Navigation was based on continuously recording direction and distance through use of a directional gyro and ...


29

The navigation system used a combination of magnetic pickups in the wheels (to count how many turns each one has taken) and a directional gyro. This allowed both turn angles and distances travelled to be calculated on board. See this section of the manual, section 1.3.7 "Drive Control Electronics" (page 5 onwards.) Also page 18 of the above link shows the ...


26

No spacecraft has been yet lost to the asteroid belt. In fact, we have the opposite example of missing an asteroid when it was even targeted, like was the case with MINERVA lander of the JAXA's Hayabusa deep space probe, missing the 25143 Itokawa asteroid. Why haven't we lost any spacecraft due to collision with asteroids in the asteroid belt is also pretty ...


21

(originally answered to "Samples of old guidance software") The first that comes to mind is the Github repository of the Apollo 11 Guidance Computer (AGC). The repository has both Command Module and Lunar Module software, but note that it is transcribed from hardcopies, so it might not be fully complete (yet). You can find a simulator of the AGC on the ...


20

Here is a good tutorial on the navigation of deep space vehicles. The two main data types used are two-way Doppler (using an atomic clock reference at the DSN station, with the frequency locked to and sent back to Earth by the spacecraft), which gives the velocity component along the Earth-spacecraft line to better than 0.1 mm/s, and ranging (sending a ...


20

The location of the North Pole is 21.18 RA, 52.89 North. There is no "North Star" located there, although it is about half-way between Deneb and Alderamin. (Source). In the sourthern sky, Kappa Velorum is a good South Pole Star. Here's also a few screenshots as to what the poles would look like: Mars North Pole: Mars South Pole: I've also added a bit of ...


20

There are two problems here: Where am I (and what is my velocity vector in some inertial frame of interest)? (Navigation) (that's what I suppose you are asking) Am I flying head over heels or vice versa (and how fast am I rotating)? (Attitude determination) For navigation: The prevailing mode of thinking considers X-ray pulsars to be the principal avenue ...


19

Zero. Voyager 1 has left the solar system, and is therefore an interstellar spacecraft. I'm not sure what qualifies a ship, but there is no reason why it would take any humans. Nor do yachts (or cars) need humans for navigation, for that matter. Interstellar space is particularly dull. You'll be travelling for many years with absolutely nothing ...


18

Not the way GPS works, no, since the Mars orbiters don't have atomic clocks. (Though future Mars orbiters may someday.) The relay radios on the Mars orbiters provide a 2-way Doppler data type that can be used to locate surface assets to, as I recall, within about 100 meters. Even a single orbiter with Doppler data collected over a few passes can get this ...


18

In many of the early probes, up until close to Apollo there were not true computers on space probes. All computing was done on earth and the onboard electronics was known as a sequencer, for Pioneer 10 it had 222 possible commands 5 of which could be readied. Early Venus probes sent data by mechanically switching different sensors to modulate a CW ...


17

If long-range navigation is necessary, a combination of inertial navigation with occasional position fixes using stars gives reasonably accurate navigation. Inertial navigation has a few drawbacks: high cost and these systems become less accurate over time (hence the need for occasional position fixes). For short-range navigation, dead reckoning may be ...


16

Yes, a properly functioning accelerometer that is stationary relative to the surface of the Earth will read the acceleration due to gravity. If it's a very good accelerometer, you could also see the factor of a few hundred smaller decrement in that acceleration due to the centripetal acceleration from the rotation of the Earth. If it's a really really good ...


16

The rovers used a gyroscope-based navigation system. The Lunar Roving Vehicle (LRV) navigation system consists of a directional gyro, a set of incremental odometers, and a hybrid analog-digital signal processor plus appropriate controls and readouts. Info from Lunar Roving Vehicle Navigation System Performance Review, (NASA Tech Note D-7469)


15

There are a few things that could be done (Using pretty heavily "A Case for Mars" second edition): There will not be full constellation of satellites, but undoubtedly there will be satellites orbiting Mars at that time that are functioning. Each Mars orbiter since Mars Global Surveyor has included some sort of a beacon which could be heard. Measuring ...


15

GPS is regularly used in low earth orbit. It is possible to use the signals from the sidelobes of the GPS transmit antennas to receive service in a high earth orbit up to and potentially beyond geosynchronous altitude: (Image credit: GPS World) However, it is challenging because the signals are substantially weaker and coverage is intermittent. These ...


14

Blockchain is a very poor solution to a specific problem: achieving ledger consensus among a large number of agents when there is substantial incentive to corrupt the record, and the entries in the ledger are directly related to one another. This is not a good fit to a satellite ephemeris. A relatively small number of agents add records to the system at a ...


13

The Voyager Attitude and Articulation Control Subsystem uses a sun sensor to point the high-gain antenna at the sun. This is simple: rotate the spacecraft until you find the brightest spot in the sky. When this is done, the spacecraft's attitude is known in two of the three axes (X and Y). To fix the third axis (Z), the spacecraft rotates until its star ...


13

If you can make and break this connection safely and reliably, you would be able to exchange momentum very efficiently. This is effectively what a skyhook does with the addition of making the tethered connection in reverse. Challenges: You probably won't be able to make and break this connection safely and reliably, so you will need a back-up plan! These ...


13

First of all, it's worth to mention that engine gimbaling is not the only way to control a rocket. You can use differential thrust, or vernier thrusters, or even aerodynamic flight control surfaces. But you are right on that, that all of these systems require some sort of control. The gimbaling angles can't be pre-programed, because they have to dynamically ...


13

Like the lower left part of the image below. Define a set of pulsars through describing proportions between their frequencies. Define distances from each of them. This uniquely identifies a point in space, and the pulsars are very efficient "beacons" recognizable from very far. This would determine position of Sun. As for Earth, third planet, easy.


13

They used the rendezvous radar on the LM to pinpoint the CSM's relative direction, and worked backwards from that info and the CSM's location in order to pinpoint the LM. Here's the commentary from the Apollo 11 Lunar Surface Journal at 121:00:34: [In a 2010 book, From the Trench of Mission Control to the Craters of the Moon, H. David Reed, who was ...


12

I'm a little surprised nobody has mentioned markers. As in flags, signposts, and splashes of paint on rocks. Astronauts on the first missions to Mars are not going to go all that far from their base. Vehicles won't have the range and safety considerations would limit them. Vehicle tracks remain visible for a very long time, dust storms lay down a thin layer ...


12

Let's break your question into separate tasks: Autonomous orbit determination (autonomous because the DSN won't be there to help you when you need it) Autonomous attitude determination Situational awareness for formation flying (relative positions, velocities, attitudes and attitude rates), most efficiently done in a cooperative manner Cooperative collision ...


12

Well if they did slip their navigation they can follow their tracks back to the LM. They planned for this in case of total breakdown, how much more for nav error.


12

The satellites' location is very accurately determined using ranging techniques, where a pulse is sent from a ground station to the satellite and the satellite responds very quickly, with a known time between receive/transmit. This allows one to determine exactly how far away the satellite is. Combining this information with orbital tracks allows one to ...


12

From russian wikipedia: Another instrument helped to the pilot to decide when to start manual operation to return to Earth - it was a small globe with a clock mechanism, which shows the (calculated, not measured) current location over Earth. It followed the craft position as calculated with the mechanical computer inside, following parameters initially ...


12

For satellite navigation, you are most likely using the Global Positioning System, which uses six planes of satellites at an altitude of 20,180 km. However, many systems can also use the GLONASS satellite constellation to get more satellites visible, especially near the poles. They orbit in three planes at 19,130 km. The less complete systems BeiDou and ...


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