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Goodbye, Galileo
deglr6328 writes "On the 21st of this month the Galileo Space Probe, which has been orbiting Jupiter for nearly eight years, will plummet fatefully into the crushing pressures and searing heat of that planet's interior. The spacecraft's 14 year journey has brought the discovery of, among other things, the first moon orbiting an asteroid, the first remote detection of life on earth when Carl Sagan used data from an onboard infrared spectrometer to observe the spectral signature of Oxygen in our atmosphere, it has caught snowflakes of Sulfur Dioxide as it flew through the plume of an erupting volcano on Io, snapped pictures of comet Shoemaker-Levy 9 as it smashed into Jupiter's atmosphere and most importantly, provided proof a >60 Km deep ocean on Europa with hints of oceans on Callisto and Ganymede(listen to Ganymede's eerie sounding plasma wind). And all this with scarcely more computing power than a late '70s video game and a maximum data transfer rate of ~120 bits/s over a distance of more than 600 million Km. In a mission spanning three decades, the Galileo space probe has answered many of humanity's questions about space and presented us with the knowledge to ask many more which will be answered by the next generation of Jovian explorer. Goodnight Galileo."
This month's issue of popular science has an article also. Click.
Here is the transcript of the last Galileo probe to "land on" Jupiter:
Time Event
________ _____
11:04 a.m. Coast timer initiates probe operation
12:46 p.m. Orbiter flyby of Io (~1000 km) (No imaging or spectral data collected)
2:04 p.m. Energetic Particles Investigation (EPI) begins measuring trapped radiation in a region previously unexplored.
5:04 p.m. Probe entry and data relay
5:05:52 p.m. Pilot parachute deployed
5:05:54 p.m. Main Parachute deployed
5:06:02 p.m. Deceleration module jettisoned
5:06:06 p.m. Direct scientific measurements begin
5:06:15 p.m. Radio transmission to orbiter begins
~5:08 p.m. Visible cloud tops of Jupiter reached
5:12 p.m. Atmospheric pressure the same as Earth's sea-level pressure
5:17 p.m. Second major cloud deck is encountered (uncertain)
5:28 p.m. Water clouds entered (uncertain)
5:34 p.m. Atmospheric temperature equal to room temperature on Earth
5:46 p.m. Probe enters twilight
6:04 p.m. End of baseline mission. Probe may cease to operate due to lack of battery power, attenuation of signal due to atmosphere, or being crushed.
6:19 p.m. Orbiter ceases to receive probe data (if still transmitting)
7:27 p.m. Ignition of Galileo main engine (49 minute duration) to insert into Jovian orbit
What are you talking about. Hubble was not built cheaply. And since its repair it has been one of the best things NASA has ever done. By the time they plan to retire it (~2010 I believe?), it will have been in use for just under 20 years and the Jack Webb telescope should be ready.
If the orbiter were left to circle Jupiter after running out of propellant (barring an intervention, this would likely happen within a year), it might eventually crash into Europa, one of Jupiter's large moons. In 1996, Galileo conducted the first of eight close flybys of Europa, producing breathtaking pictures of its surface, which suggested that the moon has an immense ocean hidden beneath its frozen crust. These images have led to vociferous scientific debate about the prospects for life there; as a result, nasa officials decided that it was necessary to avoid the possibility of seeding Europa with alien life-forms. And so the craft has been programmed to commit suicide, guaranteeing a fiery, spectacular end to one of the most ambitious, tortured, and revelatory missions in the history of space exploration.
That's why they are ditching it in said manner.
Holy crap. That is the dumbest thing I've ever read. First, Jupiter is HUGE. I mean *really* huge. Bigger than you can conceive! To be more specific, Jupiter is around 4.18591697 x 10^27 pounds (thank you Google Calculator). Yes, that's 4185916970000000000000000000 pounds for you folks that don't understand scientific notation.
Now, Nasa is planning on plunging 34 pounds of Plutonium into the planet. That's 3.4 * 10^1 pounds. Hmm... 10^1 versus 10^27. Do I need to say more? I mean... honestly, this is friggin' ridiculous!
Cheaper or more expensive comes down to the funding NASA gets. NASA spends the money it gets allocated. Half of "cheaper = better" is making the most of the stuff that's been built; Galileo is a prime example of this. What makes it such a great achievement is that NASA kept getting more information out of it, rather than building another expensive probe to send out there. As for reliability of new stuff, NASA recently debugged a system deadlock on Mars from Earth.
Of course, recent NASA projects haven't been particularly ambitious, because of a lack of sufficient funding for that. However, with a replacement for the shuttle fleet on Congress's minds, and shows of interest in space from Russia and especially China, NASA will hopefully get more funding to do interesting stuff (and to develop the necessary technologies, which are the really interesting results).
Every form of communications, from talking to someone in the next cubical to receiving pictures from interplanetary space probes, is bound by Shannon's Theorem, which describes the relationship between a channel's bandwidth and signal-to-noise ratio and how much information you can communicate on that channel.
Galileo was equipped with a high-bandwidth communications link capable of doing a much better job with image transmission, but its antenna failed to deploy. Because higher-bandwidth channels have a higher noise floor, a consequence of Shannon's Theorem is that higher-bandwidth wireless communications requires higher effective radiated power. Without the high-gain antenna, the normal image-transmission link was useless. As a result, the project engineers had to reconfigure a low-power, low-bandwidth auxiliary link to do the same job.
It was actually really cool (and really lucky) that they could do that at all.
Actually after looking at the link, that wasn't such a bad processor: 6.4 mhz, 16 bit addressing (even with an 8 bit data bus) and 16 general purpose registers. That's way ahead of the average 70's CPU - I was expecting it to be something far less powerful (more like a type of Z80).
Science does make money for schools. When we get a grant for doing science, the department and/or the university gets a cut. So if a lab gets a $600,000 grant, they'll probably actually get to see only $200,000-$300,000 of it or so, depending (greatly) on the university. For instance, in the grant administration booklet for my university it looks like 49% of a grant goes directly to the university for "Facilities and Administration." Then there are another 70 pages of crud I'm not going to look at which nibbles away the grant further. Given an article in the student paper last year saying with pride that the football team was now one of the few in the country to be so profitable as to hit the break-even point and my university's perverse overspending on athletics and consistent underfunding of maintenence and faculty pay (2nd lowest in the country, baby!), I imagine "Facilities and Administration" is simply a euphanism for "Athletics Department."
If you just look at a university's budget and see X income from grants and Y from ticket sales and etc., and expenditures X/2 for research and 2Y for athletics (after all, only men's football and basketball programs ever have a hope in hell of ever reaching the break even point--sad but true for now) then athletics are just a drain on the university. But I'm not so blinded by my intense hatred of the Athletics Department to say that it doesn't bring in money--it just does so in a very roundabout way. Private donations are very important to the survival of the university. People might donate becuase of a sense of pride in the university or out of nostalgia, but while academic research doesn't rank high on most people's minds for either of these two things, the old football and basketball teams often do. Similarly, a good sports program may grease the wheels a bit for what little funding we get through the state. How much income from private donations and the state can be indirectly attributed to athletics is very hard to say. Does it surpass research grants? Probably at some universities. But it is worth noting that there are schools that do just fine without athletics and still get piles from grants, the state, and private donations.
Galileo was supposed to be launched from the shuttle. When Challenger happened, it delayed Galileo for years. It's design phase started in late seventies, building took the early eighties but it had to be put to storage until they could find the launch equipment. This delay is also one of the reasons why Galileo cost this much. It isn't cheap to build one of these babies, let alone the clean room storage area.