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.

A Snow Moon—the Year’s Brightest Supermoon—Will Be Visible Next Week

iStock.com/jamesvancouver
iStock.com/jamesvancouver

Save the date: The next supermoon is set to light up skies on Tuesday, February 19. Because of when it's arriving, the event will also be a snow moon—a type of full moon that can only been seen this time of year, USA Today reports.

What is a supermoon?

A supermoon occurs when the moon is at its largest in the night sky. That means the Moon is not only full, but also at the point in its orbit that brings it closest to Earth—a position called perigee. On Tuesday, the Moon will appear 14 percent larger and 30 percent brighter than when it's farthest from our planet, making it the brightest supermoon of 2019.

This next supermoon will also have a fun nickname that fits the season. The full moon of each month has a special name. A harvest moon, the first full moon of September, is the best-known moniker, but there are also strawberry moons (June), sturgeon moons (August), and so on. A snow moon is the name for the full moon in February, alluding to February being the snowiest month of the year in the U.S.

When to watch the next supermoon

If the weather is clear in your area, the best time to see the super snow moon is early Tuesday morning on February 19, when the moon reaches its perigee. The Moon will become officially full six hours later at 10:53 a.m. EST. Sunday, Monday, and Tuesday nights will also offer spectacular views of a seemingly huge, nearly full moon.

Supermoons usually happen just a few times a year, but skygazers won't have to wait long for the next one: There's a super worm moon coming March 21, 2019.

[h/t USA Today]

11 Photos From the Opportunity Rover's Mission on Mars

NASA
NASA

In 2004, the rover Opportunity landed on Mars. Originally intended to serve a mere 90-day mission, the rover instead beamed back scientific discoveries for 15 years. But since a massive dust storm in 2018, the rover Opportunity ceased sending data—and now, NASA has declared its groundbreaking mission complete. (Its twin rover, Spirit, ended its mission in 2011.) Opportunity is the longest-serving robot ever sent to another planet. Let's celebrate Opportunity's Mars mission with a look at the images it captured.

1. Opportunity rover gets its first 360° shot.

Rover Opportunity's 360° photo of Mars
NASA/JPL/Cornell 

This 360° panorama, comprised of 225 frames, shows Mars as it was seen by the Opportunity rover on February 2, 2004. You can see marks made by the rover's airbags, made as Opportunity rolled to a stop. Here's a larger version of the photo.

2. Opportunity rover finds a meteorite.

Opportunity rover's photo of a meteorite on Mars
NASA/JPL/Cornell

This meteorite, found by Opportunity on January 19, 2005, was the first meteorite ever identified on another planet. The rover's spectrometers revealed that the basketball-sized meteorite was composed mostly of iron and nickel.

3. Opportunity rover shoots the Erebus Crater and drifts.

Opportunity rover's photo of Erebus craters and drift
NASA/JPL-Caltech/Cornell

On October 5, 2005—four months after Opportunity got stuck in an area NASA nicknamed "Purgatory Dune"—the rover skirted wind-deposited drifts in the center of the Erebus Crater, heading west along the outcrop (the light-toned rock) on the crater's rim, and snapped this photo with its PanCam.

4. Opportunity rover captures Martian rock layers.

Opportunity rover's photo of layers on Mars
NASA/JPL/Cornell

Located on the western ledge of the Erebus Crater, this ledge—called "Payson"—has a diverse range of primary and secondary sedimentary layers formed billions of years ago. According to NASA, "these structures likely result from an interplay between windblown and water-involved processes." Opportunity snapped this photo on April 5, 2006.

5. Opportunity rover comes to Cape Verde.

Opportunity rover's photo of Cape Verde
NASA/JPL-Caltech/Cornell

On October 20, 2007, Opportunity celebrated its second Martian birthday (one Martian year = 687 Earth days) by snapping this photo of Cape Verde, a promontory that juts out of the wall of the Victoria Crater. Scattered light from dust on the front sapphire window of the rover's camera created the soft quality of the image and the haze in the right corner.

6. and 7. Opportunity rover is hard at work on Marquette Island.

Opportunity rover's photo of Marquette Island
NASA/JPL-Caltech

This photo shows Opportunity approaching a rock called "Marquette Island" on November 5, 2009. Because its dark color made it stick out, the rover team referred to the rock—which investigations suggested was a stony meterorite—as "Sore Thumb." But it was eventually renamed, according to NASA, using "an informal naming convention of choosing island names for the isolated rocks that the rover is finding as it crosses a relatively barren plain on its long trek from Victoria Crater toward Endeavour Crater."

On November 19, 2009, the rover used its rock abrasion tool to analyze a 2-inch diameter area of Marquette, which scientists called "Peck Bay."

8. Opportunity rover encounters SkyLab Crater.

Opportunity rover's photo of SkyLab Crater
NASA/JPL-Caltech

Opportunity snapped a photo of this small crater, informally called Skylab, on May 12, 2011. Scientists estimate that the 30-foot crater was formed within the past 100,000 years. Click the photo for a larger version. You can also see the crater in stereo if you have a pair of anaglyph glasses!

9. Opportunity rover sees its shadow.

Opportunity rover's selfie
NASA/JPL-Caltech

On its 3051st day on Mars (August 23, 2012), Opportunity snapped this photo of its own shadow stretching into the Endeavour Crater.

10. Opportunity rover sees its first dust devil.

Opportunity rover's photo of a dust devil
NASA/JPL-Caltech/Cornell University/Texas A&M

Though its twin rover, Spirit, had seen many dust devils by this point, Opportunity caught sight of one for the first time on July 15, 2010.

11. Opportunity rover snaps a selfie.

Opportunity rover's self-portrait
NASA/JPL-Caltech/Cornell University/Arizona State University

A girl sure can get dusty traversing the Martian plains! Opportunity snapped the images that comprise this self-portrait with its panoramic camera between January 3 and January 6, 2014, a few days after winds blew off some of the dust on its solar panels. The shadow belongs to the mast—which is not in the photo—that the PanCam is mounted on.

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