On This Day in 1962, NASA Launched and Destroyed Mariner 1

NASA // Public Domain
NASA // Public Domain

On July 22, 1962, NASA launched the Mariner 1 probe, which was intended to fly by Venus and collect data on its temperature and atmosphere. It was intended to be the first interplanetary craft—the first time humans had sent a space probe to another world. Unfortunately, NASA aborted the mission 293 seconds after launch, destroying the probe in the Atlantic. What happened?

First off, a bit of history. Mariner 1 was based on the pre-existing Block 1 craft used in the Ranger program, which was aimed at gathering data on our moon. Those early Ranger probes didn't do so well—both Ranger 1 and Ranger 2 suffered early failures in orbit. Mariner 1 was a modified version of the Ranger design, intended for a much longer mission to another planet. It lacked a camera, but had various radiometers, a cosmic dust detector, and a plasma spectrometer—it would be capable of gathering data about Venus, but not pictures per se.

The two previous Ranger missions had used basically the same launch system, so it was reasonably well-tested. The Ranger probes had made it into orbit, but had been unable to stabilize themselves after that.

Mariner 1 launched on the evening of July 22, 1963. Its Atlas-Agena rocket was aided by two radar systems, designed to track data on velocity (the "Rate System") and distance/angle (the "Track System") and send it to ground-based computers. By combining that data, the computers at Cape Canaveral helped the rocket maintain a trajectory that, when separated, would lead Mariner 1 to Venus.

Part of the problem involved in handling two separate radars was that there was a slight delay—43 milliseconds—between the two radars' data reports. That wasn't a problem by itself. The Cape computer simply had to correct for that difference. But in that correction process, a problem was hiding—a problem that hadn't appeared in either of the previous Ranger launches.

To correct the timing of the data from the Rate System—the radar responsible for measuring velocity of the rocket—the ground computer ran data through a formula. Unfortunately, when that formula had been input into the computer, a crucial element called an overbar was omitted. The overbar indicated that several values in the formula belonged together; leaving it out meant that a slightly different calculation would be made. But that wasn't a problem by itself.

The fate of Mariner 1 was sealed when the Rate System hardware failed on launch. This should not have been a fatal blow, as the Track System was still working, and Ground Control should have been able to compensate. But because that overbar was missing, calculations on the incoming radar data went wonky. The computer incorrectly began compensating for normal movement of the spacecraft, using slightly incorrect math. The craft was moving as normal, but the formula for analyzing that data had a typo—so it began telling Mariner 1 to adjust its trajectory. It was fixing a problem that didn't exist, all because a few symbols in a formula weren't grouped together properly.

Mariner 1's rocket did as it was told, altering its trajectory based on faulty computer instructions. Looking on in horror, the Range Safety Officer at the Cape saw that the Atlas rocket was now headed for a crash-landing, potentially either in shipping lanes or inhabited areas of Earth. It was 293 seconds after launch, and the rocket was about to separate from the probe.

With just 6 seconds remaining before the Mariner 1 probe was scheduled to separate (and ground control would be lost), that officer made the right call—he sent the destruct command, ditching Mariner I in an unpopulated area of the Atlantic.

The incident was one of many early space launch failures, but what made it so notable was the frenzy of reporting about it, mostly centered on what writer Arthur C. Clarke called "the most expensive hyphen in history." The New York Times incorrectly reported that the overbar was a "hyphen" (a reasonable mistake, given that they are both printed horizontal lines) but correctly reported that this programming error, when coupled with the hardware failure of the Rate System, caused the failure. The bug was identified and fixed rapidly, though the failed launch cost $18,500,000 in 1962 dollars—north of $150 million today.

Fortunately for NASA, Mariner 2 was waiting in the wings. An identical craft, it launched just five weeks later on August 27, 1962. And, without the bug and the radar hardware failure, it worked as planned, reaching Venus and becoming the first interplanetary spacecraft in history. It returned valuable data about the temperature and atmosphere of Venus, as well as recording solar wind and interplanetary dust data along the way. There would be 10 Mariner missions in all [PDF], with Mariner 1, 3, and 8 suffering losses during launch.

For further reading, consult this Ars Technica discussion, which includes valuable quotes from Paul E. Ceruzzi's book Beyond The Limits—Flight Enters the Computer Age.

The Leonid Meteor Shower Peaks This Weekend—Here's the Best Way to See It

NASA/Getty Images
NASA/Getty Images

The Leonid meteor shower will be making its annual appearance in the sky this weekend. As NPR reports, the best time to catch it will be late Saturday night into Sunday morning (November 17-18)—so if you really want to catch this dazzling light show, you may want to drink some coffee to help you stay up.

The waxing gibbous Moon will dull the meteors’ shine a little, so plan to start stargazing after the Moon has set but before dawn on Sunday. (You can use timeanddate.com to figure out the moonset time in your area. The site also features an interactive meteor shower sky map to track visibility conditions.)

If you'll be in parts of the South or Midwest this weekend, you're in luck. Florida, Alabama, Mississippi, Nebraska, and Nevada are expected to enjoy the best view of the Leonids this time around, according to Popular Mechanics.

The Leonids occur every year around November 17 or 18, when Earth drifts across the long trail of debris left behind by the comet Tempel-Tuttle. The comet takes 33 years to complete its orbit around the Sun, and when it reaches perihelion (its closest approach to the Sun), a Leonid storm may occur depending on the density of the comet's existing debris. This sometimes results in hundreds of thousand of meteors streaking across the sky per hour, viewable from Earth. The last Leonid storm occurred in 2001, but Earth may not see dense debris clouds until 2099, according to the American Meteor Society.

This year, if skies are clear and you can a secluded spot away from city lights, you might be able to see around 15 to 20 meteors per hour. They travel at 44 miles per second “and are considered to be some of the fastest meteors out there,” NASA says. They’re also known for their “fireballs”—explosions of light and color—which tend to last longer than a typical meteor streak.

[h/t NPR]

Two Harvard Scientists Suggest 'Oumuamua Could Be, Uh, an Alien Probe

ESO/M. Kornmesser
ESO/M. Kornmesser

An odd, cigar-shaped object has been stumping scientists ever since it zoomed into our solar system last year. Dubbed 'Oumuamua (pronounced oh-MOO-ah-MOO-ah), it was first seen through the Pan-STARRS 1 telescope in Hawaii in October 2017. 'Oumuamua moved at an unusually high speed and in a different kind of orbit than those of comets or asteroids, leading scientists to conclude that it didn't originate in our solar system. It was the first interstellar object to arrive from somewhere else, but its visit was brief. After being spotted over Chile and other locales, 'Oumuamua left last January, leaving lots of questions in its wake.

Now, two researchers at Harvard University bury a surprising suggestion in a new paper that analyzes the object's movement: 'Oumuamua could be an alien probe. Sure, why not?

First, astrophysicists Shmuel Bialy and Abraham Loeb argue that 'Oumuamua is being driven through space by solar radiation pressure, which could explain its uncharacteristic speed. But for that theory to work, they calculate that the object must be unusually thin. Bialy and Loeb then analyze how such a slender object might withstand collisions with dust and gases, and the force of rotation, on its interstellar journey.

Then things get weird.

"A more exotic scenario is that 'Oumuamua may be a fully operational probe sent intentionally to Earth vicinity by an alien civilization," they write [PDF]. They suggest that ‘Oumuamua could be be a lightsail—an artificial object propelled by radiation pressure—which also happens to be the technology that the Breakthrough Starshot initiative, of which Loeb is the advisory committee chair, is trying to send into space. "Considering an artificial origin, one possibility is that 'Oumuamua is a lightsail, floating in interstellar space as a debris from an advanced technological equipment,” they write.

Their paper, which was not peer-reviewed, was posted on the pre-print platform arXiv.

Loeb is well known for theorizing about alien tech. He previously suggested that intense radio signals from 2007 could be the work of aliens who travel through space on solar sails. However, Loeb acknowledged that this theory deals more with possibility than probability, The Washington Post noted. “It’s worth putting ideas out there and letting the data be the judge,” Loeb told the paper last year.

[h/t CNN]

SECTIONS

arrow
LIVE SMARTER