Tag Archives: explorer 8

[June 30, 1961] Reaping the Harvest (June 1961 space science results)

June was a busy month for space travel buffs, especially those who live in the Free World.  Here’s an omnibus edition covering all of the missions I caught wind of in the papers or the magazines:

Little lost probe

The Goddess of Love gets to keep her secrets…for now.  The first probe aimed at another planet, the Soviet “Venera,” flew past Venus on May 19.  Unfortunately, the spacecraft developed laryngitis soon after launch and even the Big Ear at Jodrell Bank, England, was unable to clearly hear its signal.

The next favorable launch opportunity (which depends on the relative positions of Earth and Venus) will occur next summer.  Expect both American and Soviet probes to launch then.

X Marks the Spot

Just as planes use fixed radio beacons to determine their position, soon submarines (and people!) will be able to calculate where they are by listening to the doppler whines of whizzing satellites.  Transit 4A, launched by the Navy, joined the still-functioning Transit 2 on June 29 (#3 conked out March 30, and #1’s been off the air since last July). 

This Transit has an all-new power source.  Instead of batteries or solar panels, it gets its juice from little nuclear reactors.  These aren’t aren’t like the big fission plants you see being established all over the country.  Rather, they are powered by the heat of radioactive decay.  These energy packs are small and much simpler than solar panels.  Expect to see them used quite a bit on military satellites.

The Navy gets extra points for making their rocket do triple-duty: Also boosted into orbit were Injun 1 and Solrad 3.  The first is another University of Iowa particle experiment from the folks who discovered the Van Allen Belt; the latter a solar x-ray observatory.

Along a dusty trail

Contrary to popular belief, outer space is not empty.  There are energetic particles, clouds of dust, and little chunks of high-speed matter called micrometeorites.  All of them pose hazards to orbital travel.  Moreover, they offer clues as to the make-up and workings of the solar system. 

Prior satellites have tried to measure just how much dirt swirls around in orbit, but the results have been vague.  For instance, Explorer 8 ran into high-speed clouds of micrometeorites zooming near the Earth late last year corresponding with the annual Leonids meteor shower.  Vanguard 3 encountered the same cloud in ’59, around the same time.  But neither could tell you precisely how many rocks they ran into; nor could previous probes.

NASA’s new “S(atellite)-55” is the first probe dedicated to the investigation of micrometeorites.  It carries five different experiments — a grid of wires to detect when rocks caused short circuits, a battery of gas cells that would depressurize when impacted, acoustic sounding boards…the whole megillah.  It is one of those missions whose purpose is completely clear, accessible to the layman, unarguably useful.

Sadly, the first S-55, launched today from Wallops island, failed to achieve orbit when the third stage of its Scout rocket failed to ignite. 

It’s a shame, but not a particularly noteworthy one.  The Scout is a brand new rocket.  We can expect teething troubles.  Every failure is instructive, and I’ll put good money on the next S-55, scheduled for launch in August.

Worth the Wait

Speaking of Explorer 8, Aviation Week and Space Technology just reported the latest findings from that satellite.  Now, you may be wondering how a probe that went off the air last December could still generate scientific results.  You have to understand that a satellite starts returning data almost immediately, but analysis can take years. 

I’d argue that the papers that get published after a mission are far more exciting than the fiery blast of a rocket.  Your mileage may vary.  In any event, here’s what the eighth Explorer has taught us thus far (and NASA says it’ll be another six months until we process all the information it’s sent!):

1) The ionized clouds that surround a metal satellite as it zooms through orbit effectively double the electrical size of the vehicle.  This makes satellites bigger radar targets (and presumably increases drag).

2) We now know what causes radio blackouts: it is sunspot influence on the lower ionosphere. Solar storms create turbulence that can cut reception.

3) The most common charged element in the ionosphere is oxygen.

4) The temperature of the electrons Explorer ran into was about the same as uncharged ionospheric gas – a whopping 1800 degrees Kelvin.

This may all seem like pretty arcane information, but it tells us not just about conditions above the Earth, but the fundamental behavior of magnetic fields and charged particles on a large scale.  Orbiting a satellite is like renting the biggest laboratory in the universe, creating the opportunity to dramatically expand our knowledge of science.

Air Force discovers Pacific Ocean

The 25th Discoverer satellite, a two-part vehicle designed to return a 300 pound capsule from orbit, was successfully launched June 16.  Its payload was fished from the Pacific Ocean two days later, the recovery plane having failed to catch it in mid-descent.  I recently got to see one of those odd-tailed Fairchild C-119 aircraft that fly those recovery missions; they’re bizarre little planes, for sure. 

As for the contents of the space capsules, it’s generally assumed that they carry snapshots of the Soviet Union taken from orbit.  This time around, however, the flyboys included some interesting experiments: three geiger tubes, some micrometeroid detectors, and a myriad of rare and common metals (presumably to see the effects of radiation upon them). 

You may be wondering what happened to Discoverers 23 and 24 (the last Discoverer on which I’ve reported was numbered 22).  The former, launched on April 8, never dropped its capsule; the latter failed to reach orbit on June 8.  Unlike NASA, the Air Force gives numbers to its failed missions.

Next Mercury shots planned

Virgil I. “Gus” Grissom is set to be the next Mercury astronaut in late July.  His flight will be a duplicate of Alan Shepard’s 15 minute jaunt last month.  If all goes well, astronaut John Glenn will fly a similar mission in September.

I don’t think the Atlas is going to be ready in time this year for an orbital shot.  That means there will be several tense months during which the Soviets could upstage us with yet another spectacle. 

[February 13, 1961] Venus Plus USSR (Venera)

Look out, Venus!  The Russians are coming to open your shell.

Venus, forever shrouded in a protective layer of clouds, may soon be compelled to give up her secrets to a 1400 pound probe.  Launched by the Soviet Union on the 11th, it is the first mission from Earth specifically designed to investigate “Earth’s Twin.”

The solar-powered ship is armed with a panoply of scientific instruments, from cameras to spectrometers to magnetometers.  It’s also got a cargo of Soviet pennants and medals to deposit on the Venusian surface a la Luna 2.  It will reach the vicinity of Venus in three months; a full report might not be forthcoming until 1962.  That may seem a long while to wait for results, but one should remember that science takes time—even for nearby probes.  For instance, NASA is only just now processing the data from Explorer 8 (launched into Earth orbit last November, it fell silent just after Christmas.)

The Soviet probe (some reports call it ‘Venera’–Russian for Venus) is not the first deep space mission.  That honor goes to the American Pioneer 5).  Venera is the first ship to be launched from an orbital rocket; the Soviets report that they launched a larger vehicle into orbit, and that Venera took off from there.

This is very interesting given last week’s mystery launch, dubbed Sputnik 7.  As you may recall, the USSR launched a seven ton craft into orbit on the 4th, reportedly to do some near Earth space science.  No beep-beeps have been detected from the vehicle (though its presence has been confirmed by Western astronomers), and the Russians have been unusually quiet about the launch.  That usually indicates some kind of failed mission.

Now, my daughter has an interesting theory.  She believes that it is actually a spy satellite, and that the Soviet caginess is a ploy to lull the West into thinking the mission had been a bust. 

On the other hand, the Venera plus rocket plus fuel combination must have weighed far more than three quarters of a ton.  Is it possible that Sputnik 7 was really Venera 0, and the Venus probe never detached from its mothership? 

Maybe the Russians will tell us…in about a hundred years.

[November 4, 1960] Less is More (the launch of Explorer 8!)

Have you ever listened to a pleasant radio broadcast only to have it fade out half-way and wondered what caused the interruption?  Or perhaps you’ve marveled at how, on rare occasions, you can catch programs from faraway countries.

NASA’s about to take some of the mystery out of these phenomena.  Yesterday, the space agency successfully launched number eight in its Explorer series of small science satellites, the first in over a year.  The 41kg probe has a brand-new type of mission, to explore the ionosphere–the upper atmospheric layer where atoms are violently stripped of their electrons by the merciless Sun, thus ionizing them. 

This region has some fascinating properties, most significant of which is its ability to reflect radio waves.  This is why you can pick up shortwave broadcasts from around the globe.  The ionosphere is also a quicksilver place whose ability to relay radio changes by the minute. 

Until today, the ionosphere had only briefly been probed by suborbital sounding rockets or by satellites on their way to orbit on other errands.  Explorer 8 was purpose-built for the task of ionospheric study by Goddard Space Flight Center in Maryland, NASA’s first established research center.  As Explorer dips low in its eccentric orbit, four of its seven experiments measure the electrical charge on the probe’s surface, the temperature of the electrons around the satellite, the total electrical current rushing over the satellite’s skin, and the concentration of charged particles around the probe.  Two other experiments measure the density of micrometeoric dust, and the final one allows measurement of atmospheric density.  Interestingly, there are no solar panels on Explorer 8, as they would interfere with its ability to take measurements.  We can expect a couple of months of good, battery-fueled data collection, however.

In plain English, Explorer 8 will give us our first true map of a crucially important piece of our atmosphere.  The ionosphere is, essentially, our first sea wall against the ocean of space.  Not only will we better understand radio propagation, we will also be able to quantify atmospheric electricity and analyze the base of our planet’s magnetosphere. The instruments on Explorer 8 will be refined for use in future probes to other planets, letting us study them with similar comprehensiveness. 

It’s great news, but the really exciting bit is that the Explorer 8’s rocket, the Army’s Juno II, worked at all.  The booster was developed by Von Braun’s Huntsville, Alabama team back in 1958 as a competitor to the Air Force’s Thor Able.  When the Army got pushed out of rocket development, the Juno II became an orphan.  As a result, the folks working on it stopped caring so much, and the rocket has since had a lackluster performance record.  At a NASA hearing this summer, there was talk of pulling the plug entirely on the program.  However, it was determined that of the four boosters left (built and paid for), at least two could be expected to work.  Might as well use what you have rather than let them go to waste, I suppose.

That leaves three boosters, of which at least one will probably accomplish its task.  Anyone want to make a bet on which one it will be?