# Tag Info

## Hot answers tagged perseverance

68

I believe the mechanism is this pyro-cutter, photographed by Emily Lakdawalla here. Specifically, I think they were manufactured by PacSci EMC, since they brag about it in this Facebook post. If you'd like to buy one, they sell them here. There's a description of the cutters used by MSL (Curiosity) here with some nice pictures of it in action on page 12.

60

If you watch the coverage on YouTube, they explain hydrazine rockets burn clear. This is supported by the dust flying everywhere when it gets closer to the ground.​

59

RTG technology has been applied on Earth, many times, although not for transportation - they don't produce much power for their weight so any RTG powered vehicle would be very slow. Some pacemakers used to have plutonium batteries, and RTGs were used in remote sites to power sensors, lighthouses and the like in remote areas. It isn't used much anymore on ...

41

I think you may be confused about the nature of the problem the skycrane is trying to solve (however I also may be confused!). The rover, being a rover, does not need to stay at the landing site. If the landing site has a lot of dust blown off it, well, they can go somewhere else where the dust has not been blown off the surface. As the other answer says ...

39

It would be rather surprising if the exhaust from these engines was visible. The engines use hydrazine ($\mathrm{N_2 H_4}$) monopropellant, and the reactions involved (catalysed by iridium) are  \begin{aligned} \mathrm{N_2 H_4} &\rightarrow \mathrm{N_2 + 2H_2} &&\text{exothermic}\\ \mathrm{3N_2 H_4} &\rightarrow \mathrm{4NH_3 + N_2} &...

34

The video shows only tests within the clean room on smooth clean test floors. The vibration test at first should simulate the conditions during launch. Drive tests on a simulated Martian rough and dirty surface on Earth (see JPL Mars Yard) are not done with the version built for the Mars surface. The flight-ready version is built in a clean room and only ...

34

According to the official NASA press release, pyrotechnic guillotines were used: The footage ends with Perseverance’s aluminum wheels making contact with the surface at 1.61 mph (2.6 kilometers per hour), and then pyrotechnically fired blades sever the cables connecting it to the still-hovering descent stage. The descent stage then climbs and accelerates ...

28

RTGs are expensive to produce, can be politically inconvenient to use, and in the form of a plutonium-bearing device, represent a potential nuclear proliferation hazard (though all RTGs might be used to construct a "dirty bomb"). To compound the issue, their power output simply isn't very big... Perseverance's generator cost about 75 million USD ...

27

I'm quite sure it can move. The first roughly 9 days after landing it needs to get its bearings, look around, plan out a path, and most importantly, be reconfigured to operate on the ground. For comparison, Curiosity landed on August 6th, and didn't start moving until August 15. Perseverance landed on Feb 18, it has only been 11 days, I wouldn't worry too ...

25

It crashed and the aftermath was photographed. https://www.space.com/mars-perseverance-rover-photo-sky-crane-crash A moment of respect for the descent stage. Within two minutes of safely delivering me to the surface of Mars, I caught the smoke plume on one of my Hazcams from its intentional surface impact — an act that protected me and the scientific ...

23

This animated gif is comprised of images that were acquired by the Navigation Camera (Navcam) located on the rover mast, part of the Mastcam-Z instrument. Mastcam-Z is capable of acquiring videos (generally at about 4 frames per second), but sending this data back to Earth could take a long time. To send data to Earth, the rover transmits a signal to a ...

22

Yes, they could theoretically communicate with each other over the DSN, however in practice this will not happen (as it has no current uses). The amount of functions that Curiosity can perform autonomously is very limited and predetermined. It usually involves some sort of deterministic operation such as moving a rover arm or performing a drill sample (...

22

I asked one of the copter's engineers, Matt Keennon, what the hole in that one leg's foot was for. He replied that it's only for stowage. ... because of the odd way the copter is held in place under the rover, with all sorts of mechanical constraints from the rover, that one leg could not be held down by a simple lever pressing on the leg strut, so instead ...

22

I think it's important to understand the timeline here. The footage we've all been amazed by was acquired by a collection of slightly-hardened small, light, high-quality commercial off-the-shelf (COTS) cameras, helped by a fast, very-low-power processor (I think a Qualcomm SnapDragon: this processor is much faster than Perseverance's main processors!) and ...

22

As of today, the debris shield has been dropped. The "tests" discussed in the article are electrical, computer, and sensor tests. Nothing mechanical (other than dropping the shield) has been done yet; the helicopter is still attached to the bottom of the rover. The official NASA article dated today explains that the rover is now on its way to a ...

21

Hobbes' answer explains why live broadcast is currently not feasible from the Mars side. I'd like to complement it with why this is currently not feasible from the Earth side. Mars power budgets are not generous, so by the time spacecraft transmissions get back to Earth they are incredibly faint. The only equipment used to reliably receive these signals is ...

21

Yes and no. The no part first: Mars 2020 had sensors and effectors attached to the non-important parts of your diagram, many of which had various degrees of smarts. Star trackers are very sophisticated cameras. The have their own computers that control mode (e.g., lost in space versus locked) and that perform pattern matching on an self-contained star map. ...

19

No. Perseverance will not enter Martian orbit before descent. It would be a direct descent. For reference, here's a picture of Perseverance's landing procedure. A spacecraft entering into orbit before descent requires a fair bit of fuel. The thrusters on the Backshell are only there for mid-course corrections and for stability during descent. It does not ...

19

A color image would need three times the data and transmission time. The time needed for two black and white images is too short for a single color image. When everything works well after landing and when all status checks are done there is plenty of time for some color images. Persevance was traveling from Earth to Mars for about six months, a delay of six ...

19

Perseverance's umbilical data cable and bridles were cut by exploding bolts. This is the same method that Curiosity used. Exploding bolts are very commonly used in space missions. This is for several reasons. First, the fasteners must be strong enough to hold the pieces together throughout all of the vibrations and motion a spacecraft must endure as it ...

18

14 years is the design lifetime for the MMRTGs. The thermocouples do degrade over time while exposed to the high temperatures of the hot side and the temperature changes of the cold side. The output power of the RTGs drops over time by degradation, design lifetime ends when there is too few power left. But many RTGs did work better than conservative lifetime ...

17

2kW is not that much on Earth You've mentioned radiation and convection in your answer (you forgot conduction). Turns out the properties of Earth's atmosphere make conduction and convection way better than radiation for moving heat around. For an illustration, consider the size of a portable, 2kW, oil-filled radiator: this one lists the size as ...

17

NASA plans multiple trajectory correction maneuvers (TCMs) for their spacecraft headed toward another planet. The intent of these correction maneuvers is to bring the spacecraft back on track so as to reach the intended target. NASA has become very proud of the fact that the last few correction maneuvers have been waived off; the corrections in the early ...

17

All four cables should be parallel to each other no matter where the skycrane camera is located. – azot Maybe we can recreate this. Let's do some arts and crafts! The support cables appear to radiate from the center of the crane, while the data cable is offset. The data cable and one support cable are attached to the rover at the same point. If the camera ...

16

I really hope it won't be able to detect Hope, that's orbiting Mars, not landing on it. InSight was actually made to detect these impacts, as it can help one to understand more about Mars. Fundamentally a heat shield impacting is just a particularly dense meteor. I think it is likely it will detect Perseverance. The two are fairly close. Specifically it ...

16

If you look very closely at the video you'll find that the top-right engine is glowing red inside because, while hydrazine burns clear, the engine chamber is still 1000 °C hot. This has been explained also by Scott Manley on Youtube where you can see the footage:

15

Faster? No. The speeds of all Mars rovers so far have been limited by the navigation software or the available electrical power, not by physical capability. Spirit and Opportunity were both physically capable of driving more than 2000 meters per day, but rarely actually traveled more than 60. Curiosity is capable of moving 2200 meters per day, but can ...

15

This is an addendum to @Uwe's answer. RTG lifetime is a topic of much discussion in the planetary science community, and in particular the MMRTG being currently the only available RTG. MMRTGs decay much faster than GPHS-RTGs (see my comment to Uwe's answer), with an output power half-life of a bit over 16 years, the result of both Pu decay and unicouple ...

14

because it would prevent the rockets from contaminating the landing site. No they weren't There was some possible advantage from that, to be sure. But missions to Mars undergo serious levels of decontamination to ensure contamination from Earth doesn't happen, so the risk was marginal at best. If you meant contamination from hydrazine, that's not a ...

13

tl;dr: With technology, anything can potentially go wrong at any moment. Simplify and minimize wherever possible. Keep your eye on the prize. Run away! As soon as the "cord is cut" the crane represents an imminent threat to the \\$2.75 billion rover in several ways. It's hydrazine monopropellant engines have hot, nasty, reactive, horrible exhaust ...

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