Hot answers tagged

52

The Plutonium isotope 238 used in RTGs is highly specialized. It's not produced in large quantities routinely. Not very many radioisotope applications need that much of a highly radioactive isotope, and it's only produced in certain reactors. In fact, there was only one reactor in the USA that produced it. Nuclear stuff is expensive in general and, now that ...


25

No, I don't believe so. The reason space telescopes do well is that there's no atmosphere limiting the optical performance of the device. A telescope on a balloon is not anywhere near above the atmosphere. It's above a lot of the water in the atmosphere, which is why IR things can be better there, but there is still turbulence above it which will limit ...


24

Any isotope used as the basis for a radioisotope thermoelectric generator (RTG) has to have a short but not too short half life. A half life of several decades is ideal. Such isotopes effectively do not exist in nature. (Tritium, with a half life of 12.32 years, does exist in nature in trace amounts due to generation by cosmic rays, but the half life is a ...


11

It's not just the half-life of the material (short enough to make heat, long enough to have a slow changing energy curve) It's also the type of radiation. For instance Cs137 is plentiful and easy to separate, and it's a beta emitter, which is shieldable. But its decay products are gamma emitters, which is not shieldable. So nope. Pu238 is an alpha emitter, ...


10

According to the Washington Post, Doug Loverro shared internal information regarding the commercial lunar lander contracts with Boeing, who then tried to amend their bid over the contract for the lander. This led to concerns Loverro improperly sharing the information and giving Boeing an unfair advantage, and Loverro was asked to resign. Due to the article ...


8

The problem and its solution is described in section 16.2.4 of the mission report. Basically, the attitude of the LM was oriented in such a way that parts of the spacecraft were in the way of the the direct path between the S-band antenna and Earth. Also, some signal reflected off the surface of the moon, causing multipath interference. To make matters ...


8

Other spacecraft have been closer, but none have carried Sun-facing imagers. Source: The link you provided ("Other spacecraft" is linked to an article about Parker Solar Probe) Q: Or did Parker just not take pics of the Sun yet? A: Yes, or at least not from a distance closer than Solar Orbiter


7

I can tell you why as I’ve been involved in the project for years. When the crawler rolls over that river rock it crushes it and the resulting crushing motion releases silica dust in every form (total, inhaleable, and most importantly, respirable). When the crawler rolls out, a team of crawler technicians are escorting it both on the ground and on the ...


5

You claim that space agencies around the world "spend enormous amounts of money" and seem to imply that this money is wasted. Factually though, this is untrue. NASA's budget per year is around 22 billion dollars. That's only around 0.5% of the US's annual budget. For comparison, the DoD gets north of 600 billion dollars a year. That's around 15% ...


5

Logistically speaking, it might be more complex than it sounds. The bit that initially stuck out to me is that the South Pole launch is planned for December 2023. December means summer - it is likely that the weather window during which it is practical to fly this mission is quite narrow, only a few months. Outside of that period, recovery becomes ...


5

According to my extensive research on the topic, Mars 2020 is the name of the mission; Mars 2020 is to MSL as Perseverance is to Curiosity, but the Mars 2020 mission also includes the Ingenuity drone, which had no parallel in MSL. I don't see any references to a "science laboratory" on the Mars 2020 page.


4

Check these visualizations from NASA. Solar Orbiter will never get as close as Parker Solar Probe perihelion. That's why it can operate a camera pointed directly into the Sun and why it didn't have to wait for better shielding technology to arrive. The goal is to get the spacecraft (Parker Solar Probe) to fly through the corona at a distance of 9.5 solar ...


4

A couple more things to consider (that I haven't seen in the several existing answers) about having a James-Webb class observatory in the upper Earth atmosphere instead of at Sun-Earth L2: You've significantly degraded your available fields of view compared to Sun-Earth L2. Not only is your "below" completely occupied by Earth, but "above&...


4

Is Perseverance still in Safe Mode? Not any more: NASA's Mars rover Perseverance is fine and out of 'safe mode' as of July 31, 2020.


3

It was as of the latest update, but they were working on recovering it. They have full communication with the spacecraft as of now. The press release, issued on July 30, stated the following: Right now, the Mars 2020 mission is completing a full health assessment on the spacecraft and is working to return the spacecraft to a nominal configuration for its ...


3

JWST is to be a 6.5-meter telescope, while ASTHROS is only 2.5 meters. That's a pretty big difference. On the other hand, perhaps you could spend half the cost of JWST and engineer a 6.5-meter balloon-hosted telescope, but I'm not sure.


3

My boss had a pair loaned to him and I got to try them out briefly. The flicker wasn't noticeable much and the rendering and coordination with the image to the motion of one's head was very smooth. The images were full color, not red/blue like some old print version although they still produce and use those images routinely in science planning as well (...


2

For years, wide field infrared orbital telescopes have been touted as the best way to complete a survey of NEO objects and give a greater warning time on potential close approaches. Astronsapper's Plantetary Society article talks about this partially. For years, proposals have been put forth to build these orbiting telescopes, but there is not a strong ...


2

The place to start is by listing the science objectives of the mission. Balloon telescopes can be much less expensive than satellite borne ones, but the design of a satellite borne one allows a much longer life span, zero gravity to distort the telescope, less infrared heating from the earth, a wider field of view, and I'm sure many more things. You would ...


1

Many sources. (eg this one) mention the samples orbiting Mars in a "basketball-sized" container until collected by the Earth Return Orbiter. I haven't seen any authoritative ones saying it's also shaped like a basketball.


1

One point touched on but not expanded upon is high contrast imaging. That's less important when imaging a black hole or a nebula or galaxy because they don't change much and the image can be reconstructed. Imaging a planet orbiting next to or crossing over a star requires very high contrast and that wouldn't be possible with an airborne telescope, doubly ...


1

The JWST will be in a halo “orbit“ at the Earth-Moon L2 point, 930,000 miles from the Earth, and over four times as far away from us as the Moon is. It would need to be one impressive balloon to achieve that kind of altitude. And it has to be that far away so that its sunshade can deflect heat from both the Earth and Sun, which is necessary for an infrared ...


1

The TIROS Technical Control Center (TTCC) performed the usual spacecraft control center functions: monitoring and control of its assigned spacecraft. Monitoring: TTCC was assigned the primary responsibility for processing telemetry data and evaluating attitude and spacecraft status.....Computer processing of telemetry data ...


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