Early rocket and space probe designers seemed to know what to expect in terms of the conditions their vehicles would experience.
The Explorer 1 probe went aloft with a cosmic ray detector and a micrometor detector.
Konstantin Tsiolkovsky wrote an article titled “Exploration of Cosmic Space by Means of Reaction Devices” in 1903.
Hermann Oberth wrote Wege zur Raumschiffahrt (“Ways to Spaceflight”) in the 1920’s.
Jules Verne wrote about less-scholarly and more fantastic views of space travel in the late 1800’s.
How did these guys have any idea what to prepare for or write about? JPL and the Army’s *first *attempt at putting scientific instruments in space (Explorer 1) was a success! How did we know there wouldn’t be some sort of super-radation, or fluid-like aether, or space tarantulas?
I’m pulling this out of my hat, but I would imagine that radiation striking the Earth is attenuated by the atmosphere, and that the density of the atmosphere could be observed and calculated. That would give a ball park estimation of what to expect.
For one thing, high altitude balloons carried instruments high into the stratosphere. One thing they discovered was cosmic rays.
That’s why Explorer 1 carried a cosmic ray detector. Scientists had been doing proper research for a half century with every type of experiment and detector they could imagine.
Also space is just space, subject to known physics, not a science fiction story. Things were discovered that no one expected, like the Van Allen belts. But they were just normal physics stuff and not space tarantulas.
First of all, while the launch of Explorer 1 was a success, it was not the first attempt by the United States for orbital launch of a satellite, which would have been the failed launch of the Vanguard TV3 satellite. As you can read from the article, one of the primary goal of this mission was characterization of the charged particle environment and how it would impact ground-to-orbit communications. However, even before we ventured into orbital space or out to other planets, we could still make observations based upon mass, spectroscopic data, and simulation. Carl Sagan famous predicted the hot, dense greenhouse environment of Venus (although his specific predictions about the composition of the atmosphere were erroneous) from simulation and crude spectral data.
To your specific concerns, we can evaluate the space radiation environment via high altitude flights where radiation is not attenuated by atmosphere. We can observe from the motion of natural celestial bodies that there is no fluidic drag outside the atmosphere. And we can see, to the limits of visual acuity, that there are no large living organisms in orbit. However, these aren’t entirely obtuse questions; early developers of space probes and satellites did discover the previously unsuspected Van Allen belts (areas where protons, electrons, and other charged particles are concentrated by the Earth’s magnetic field) and the associated South Atlantic Anomaly, both of which pose hazards to spacecraft. While interplanetary space appears empty, it actually contains a diffuse flux of charged material which is constantly ejected from the Sun; while this is not dense or viscous enough to affect the flight of space probes, it enhances the solar magnetic field by several orders of magnitude and may affect delicate sensors. The Earth’s atmosphere also extends much further and fluctuates much more than anticipated prior to characterization by space exploration, hence, the increased drag due to high solar activity which resulted in the catastrophic deorbit of Skylab. And while our explorations of every major planet and many moons have yet to reveal living organisms, it is entirely possible that life, and potentially even complex and mobile life, could exist on several candidate extraterrestrial habitats, the form of which we could only wantonly guess at.
As it is, we are still discovering new and totally unexpected (and to some extent, still unexplained) phenomenon in our solar system. The intense magnetic fields of Jupiter (and the almost complete lack of one at Saturn), the surprising lack of nitrates on Mars, the noble gas, sodium tail, and fine charged dust atmosphere of Earth’s Moon are all relatively recent discoveries, and as we (hopefully) continue to explore these planets further we will doubtless learn new and surprising information about their composition and phenomena.
Also, Explorer 1 was preceded by plenty of sounding rockets, some of which traveled to the edge of space and beyond… starting with the WAC Corporaland building up to the Jupiter-C.
Great responses, everyone! Thank you for taking the time to write such detail.
Thank you for the link regarding the WAC Corporal. I’m starting to get a sense of how deep my ignorance about the early space program goes!
RE: the WAC Corporal, it seems it first exceeded the Kármán line (100km alt.) in 1948! :eek: My belief had always been that Sputnik was the first successful spaceflight. I realize now that the milestone Sputnik acheived was first successful orbit.
I’m surpised that I’ve been so misinformed. Even Wikipedia’s section on early spaceflight begins with Sputnik.
Understanding that Explorer 1 and Sputnik weren’t the first items in space has helped me picture the early engineers as more knowledgable about the conditions.
If I could pose a part 2 to my OP; what, in your opinion, was the first item we sent into space? I know there are different definitions of this threshold, so there may be multiple answers.
