Centauri Dreams rarely looks at Mercury, the operative method being generally to focus on the outer Solar System and beyond. But a new paper out of the Planetary Science Institute in Tucson (AZ) raises the eyebrows in suggesting that parts of Mercury may once have been able to shelter prebiotic chemistry and perhaps, according to the authors, even primitive life forms. Such a finding might thus extend our ideas of ‘habitable zones’ much closer to parent stars than previously assumed. It seems a long shot, given surface temperatures reaching 430? in the daytime and -180? at night, but the PSI work turns up interesting possibilities in some subsurface regions of Mercury. The heart of this research is found in the datasets returned by the MESSENGER (MErcury Surface Space ENvironment GEochemistry and Ranging) spacecraft. The Mercury orbiter identified numerous volatile-bearing surfaces on Mercury, with high abundances of sulfur, chlorine and potassium, and polar ice in permanently...

With the James Webb Space Telescope now declared 'a fully assembled observatory' by NASA, environmental tests loom for the instrument, which is now slated for launch in March of 2021. Within that context, we need to place WFIRST (Wide-Field Infrared Space Telescope), whose development was delayed for several years because of cost overruns on JWST. Recall that WFIRST was the top priority for a flagship mission in the last astrophysics Decadal Survey. The good news is that NASA has just announced that WFIRST has passed what it is calling 'a critical programmatic and technical milestone,' which opens the path to hardware development and testing. With a viewing area 100 times larger than the Hubble instrument, WFIRST will be able to investigate dark energy and dark matter while at the same time examining exoplanets by using microlensing techniques applied to the inner Milky Way. Its exoplanet capabilities could be significantly extended if additional budgeting for a coronagraph -- which...

The fault protection routines programmed into Voyager 1 and 2 were designed to protect the spacecraft in the event of unforeseen circumstances. Such an event occurred in late January, when a rotation maneuver planned to calibrate Voyager 2's onboard magnetic field instrument failed to occur because an unexpected delay in its execution left two systems consuming high levels of power (in Voyager terms) at the same time, overdrawing the available power supply. We looked at this event not long after it happened, and noted that within a couple of days, the Voyager team was able to turn off one of the systems and turn the science instruments back on. Normal operations aboard Voyager 2 were announced on March 3, with five operating science instruments that had been turned off once again returning their data. Such autonomous operation is reassuring because Voyager 2 is now going to lose the ability to receive commands from Earth, owing to upgrades to the Deep Space Network in Australia. This...

Centauri Dreams reader Charley Howard recently wrote to ask about how NASA goes about setting its mission priorities and analyzing mission concepts like potential orbiter missions to the ice giants. It's such a good question that I floated it past Ashley Baldwin, who is immersed in the evolution of deep space missions and moves easily within the NASA structure to extract relevant information. Dr. Baldwin had recently commented on ice giant mission analysis by the Outer Planets Advisory Group. But what is this group, and where does it fit within the NASA hierarchy? Here is Ashley's explanation of this along with links to excellent sources of information on the various mission concepts under analysis for various targets, and a bit of trenchant commentary. By Ashley Baldwin Each of the relevant NASA advisory groups has its own page on the NASA site with archives stuffed full of great presentations. The most germane to our discussion here is the Outer Planets Assessment Group (OPAG). My...

Are missions to the Sun particularly relevant to our interstellar ambitions? At the current state of our technology, the answer is yes. Consider Solar Cruiser, which is the planned NASA mission using a solar sail that could maintain non-Keplerian orbits, allowing it to investigate the Sun's high latitudes. And throw in the European Space Agency-led Solar Orbiter, which left our planet early Monday (UTC) on a United Launch Alliance Atlas V rocket, lifting off from Launch Complex 41 at Cape Canaveral Air Force Station in Florida. Herewith the gorgeous arc of ascent: Image: Launch of the ESA/NASA Solar Orbiter mission to study the Sun from Cape Canaveral Air Force Station in Florida on Feb. 9, 2020. Credit: Jared Frankle. Missions to the Sun allow us to explore conditions close to a star and, significantly, deep in its gravity well, where interesting things can happen. When we discuss one way of propelling a sail beyond the heliosphere, the irony is that an Oberth maneuver, which takes...

When one of our Voyagers experiences a blip of any kind, it gets my attention. It's not like we have any other options outside the heliosphere right now. Both Voyagers have fault protection software that allows the spacecraft to protect themselves if problematic situations occur. And a problem did indeed surface aboard Voyager 2 on January 25, when there seems to have been a delay in the onboard execution of commands for a scheduled maneuver. The latter was a 360 degree rotation to be executed as a way of calibrating the craft's magnetic field instrument, and the result of the delay was that two systems that consume power at relatively high levels were operating at the same time. Not a good idea. Right now, with power dwindling inexorably, the Voyager missions are both dominated by power management. Hence the shutdown of Voyager 2's science instruments to make up for the power deficit, as reported by the Voyager team on Twitter: Here's the skinny: My twin went to do a roll to...

We’re seeing our final images of asteroid Ryugu as the Hayabusa2 spacecraft leaves its orbit some 300 million kilometers from Earth. The Japanese Aerospace Exploration Agency (JAXA) intends to keep taking images of the receding Ryugu for several more days, after which it will be necessary to perform an attitude control maneuver to orient the craft for proper operation of its ion engines. An ion engine test period will culminate in cruise operations on December 3 to return the spacecraft to Earth. Image: Asteroid Ryugu captured with the Optical Navigation Camera - Telescopic (ONC-T) immediately after departure. Image time is November 13 10:15 JST (onboard time), 2019. Credit: JAXA, Chiba Institute of Technology, University of Tokyo, Kochi University, Rikkyo University, Nagoya University, Meiji University, University of Aizu, AIST. Happily, we are asked to join in JAXA’s ‘Goodbye Ryugu’ campaign by sending a #Sayonara_Ryugu tweet (https://twitter.com/haya2e_jaxa), although the agency...

It's heartening to consider that the two Voyager spacecraft, though built for a 4 ½ year mission, have continued to function ten times longer than that. This fact, and data from other missions, will help us get a handle on longevity in spacecraft systems as we contemplate pushing out beyond the heliosphere with a spacecraft specifically designed for the job. Mission longevity is mysterious for it often seems to surprise even the designers, who would like to have a more concrete sense of how to ensure operations continue for decades. Voyager 2 broke Pioneer 6's record of 12,758 days of operation way back in 2012, but we can also consider spacecraft like Landsat 5, launched in 1984 and carrying two instruments, the Multispectral Scanner System (MSS) and the Thematic Mapper (TM). Managed by the U.S. Geological Survey (USGS), Landsat 5 completed over 150,000 Earth orbits and sent back more than 2.5 million images of Earth's surface, with operations lasting almost three decades. Design...

One of these days we'll have a spacecraft on a dedicated mission into the interstellar medium, carrying an instrument package explicitly designed to study what lies beyond the heliosphere. For now, of course, we rely on the Voyagers, both of which move through this realm, with Voyager 1 having exited the heliosphere in August of 2012 and Voyager 2, on a much different trajectory, making the crossing in late 2018. Data from both spacecraft are filling in our knowledge of the heliosheath, where the solar wind is roiled by the interstellar medium. A new study of this transitional region has just appeared, led by Jamie Rankin (Princeton University), using comparative data from the time when Voyager 2 was still in the heliosheath and Voyager 1 had already moved into interstellar space. Leaving the heliosheath, the pressure of the Sun's solar wind is affected by particles from other stars, and the magnetic influence of our star effectively ends. What the scientists found is that the...

The arrival of an apparent interstellar visitor, the comet now designated C/2019 Q4 (Borisov), invariably calls to mind the all too swift passage of 'Oumuamua through our skies in 2017. Detected 40 days after perihelion, the object was headed out of the Solar system when discovered, making observation time limited and the prospects of visiting it with a probe problematic. Nonetheless, Andreas Hein and colleagues at the Initiative for Interstellar Studies put out a mission concept we reviewed in these pages. To refresh your memory, see Project Lyra: Sending a Spacecraft to 1I/'Oumuamua (formerly A/2017 U1), the Interstellar Asteroid). Image: C/2019 Q4 (Borisov), in the center of the image. Note what appears to be a short tail extending from the coma. Credit: Gennady Borisov. The mission the authors described stretched the boundaries of the technologically possible, not to mention the resources that would be available for such an attempt. But now we have a second interstellar wanderer,...

You would think that heading toward the Sun, rather than away from it, would not necessarily fall under Centauri Dreams’ purview, but missions like the Parker Solar Probe have reminded us that extreme environments are ideal testing grounds for future missions. Build a heat shield that can take you to within 10 solar radii of our star and you’re also exploring possibilities in ‘sundiver’ missions that all but brush the Sun in a tight gravity assist. Or consider the two proposals NASA has just selected in the area of small satellite technologies, which grow directly out of its heliophysics program. Here, the study of the Sun’s interactions with the Solar System, and the consideration of Sun, planets and heliosphere as a deeply interconnected system, takes pride of place. Let’s start with a mission called SETH -- Science-Enabling Technologies for Heliophysics. One of its two technology demonstrators, called the HELio Energetic Neutral Atom (HELENA) detector, involves solar energetic...

Al Jackson shares more memories of Apollo this morning in his account of a little known spacecraft component, the Abort Guidance System. A NASA historical document on computers aboard the Apollo spacecraft refers to the Abort Guidance System as "...probably the most obscure computing machine in the manned spaceflight program to date." The AGS was a backup computer system offering the capability of aborting the mission if the Lunar Module's primary guidance system failed during descent to the lunar surface, ascent or rendezvous. The very invisibility of the system is in its way a tribute to the primary guidance and navigation systems, for while the AGS could abort a landing, it was never needed for that purpose. But NASA's abort policy made its presence mandatory -- an abort would be ordered if one additional system failure could potentially cause the loss of the crew. Thus a loss of either the primary guidance and navigation control system or the AGS would have caused an abort....

One of the many legacies of the Voyager spacecraft is the Interstellar Mapping and Acceleration Probe (IMAP). Scheduled for a 2024 launch, IMAP has as part of its charter the investigation of the solar wind's interactions with the heliosphere, drawing on data from an area into which only the Voyagers have thus far ventured. Let me hasten to add that IMAP will stay much closer to home, orbiting the Sun-Earth L1 Lagrange point, but like the Interstellar Boundary Explorer (IBEX), it will help us learn more about a region physically reachable only by long-duration craft. The fact that we're still talking about Voyager as an ongoing mission is the story here. Launched in 1977, the doughty probes have kept surprising us ever since. In terms of their longevity, I noted in 2017 that when Voyager 1's thrusters had begun to lose their potency (they're needed to keep the spacecraft's antenna pointed at Earth to return data), controllers were able to fire a set of backup thrusters that hadn't...

I'm staying in Apollo mode this morning because after Friday's piece about the Lunar Module Simulator, Al Jackson forwarded two further anecdotes about his work on it that mesh with the discussion. Al also reports that those interested in learning more about the LMS can go to the official Lunar Module familiarization manual, which is available here. I've also inserted some background on the LMS, with my comments in italics. by Al Jackson A couple of funny anecdotes about the Lunar Module Simulator. It took some effort to get the LMS up and running … we could do a little simulation when it was first installed, but I had a very irregular schedule. I always worked at the LMS crew training 8 am to Noon, but for most of 1967, because the crew did not train after 5 pm, I came many the night with the Singer engineers to test the LMS, sometimes 6 to midnight, sometimes midnight to 7 am, and yeah I had to stick around for the 8 am to noon shift, and then go home and sleep. There was a...

While compiling materials for a book on Apollo 11, Neil McAleer accumulated a number of historical items that he passed along to me (thanks, Neil!), and I'm thinking that with the 50th anniversary of the first landing on the Moon approaching, now is the right time to publish several of these. Centauri Dreams has always focused on deep space and interstellar issues, but Apollo still carries the fire, representative of all human exploration into territories unknown. In the piece that follows, Neil talked to Al Jackson, a well known figure on this site, who as astronaut trainer on the Lunar Module Simulator (LMS) worked with Neil Armstrong and Buzz Aldrin before Apollo 11 launched, along with other Apollo crews. McAleer finalized and synthesized the text, which I'll follow with a piece Al wrote for Centauri Dreams back in 2012, as it fits with his reminiscences related to McAleer. I've also folded in some new material that Al sent me this morning. by Al Jackson and Neil McAleer In the...

Recent tests of a 'wafer-craft', an early prototype for what may one day be the 'starchip' envisioned by scientists involved with the Breakthrough Starshot project, have been successful. The work grows out of a NASA-funded effort led by Philip Lubin (UC Santa Barbara), whose investigations into large scale directed energy systems began in 2009. Lubin went on to perform multiple studies for NASA's Innovative Advanced Concepts program developing the idea that would become known as DEEP-IN (Directed Energy Propulsion for Interstellar Exploration). His NIAC Phase 1 report studied as one option beamed propulsion driving a wafer-scale spacecraft. Renamed Starlight, the proposal went on to Phase II funding as well as support from the private sector. A subsequent review by Breakthrough Initiatives led to endorsement of the concept within its Breakthrough Starshot effort. Breakthrough is devoting $100 million to studying the viability of sending a 'starchip' to a nearby star such as Proxima...

The exuberance of images like the one below captures the drama of Solar System exploration. Scenes like this are emblematic of the early reconnaissance of the Solar System. We saw similar enthusiasm with missions near and far -- I'm thinking back, for example, not just to Voyager, but the Viking landings on Mars, and I'm sure Russian controllers were equally jubilant when their Venera craft touched down on Venus. Space is indeed the 'final frontier,' as James T. Kirk reminded us on Star Trek, and it's a frontier that goes on without end. Image: Celebration in full swing as scientists react to the view from New Horizons after the Ultima Thule flyby. Credit: NASA / JHUAPL / SwRI / Henry Throop. Let's keep in mind, then, that New Horizons is not just returning Ultima Thule data, but continuing to push into the Kuiper Belt doing good science. In terms of future missions, we need to learn as much as we can about radiation, gas and dust as we assess the environment. New Horizons will get...

We've just learned that New Horizons is intact and functional, with a 'phone home' message at about 1530 UTC that checked off subsystem by subsystem -- all nominal -- amidst snatches of applause at the Johns Hopkins Applied Physics Laboratory. The solid state recorders (SSR) are full, with pointers indicating that flyby information is there for the sending, even as the spacecraft continues with outbound science. New Horizons will pass behind the Sun in early January, giving us a break in communications for a few days this weekend. Over the next 20 months we will get the entire package from Ultima Thule. Patience will be in order. Here's the approach image that was released yesterday. Image: Just over 24 hours before its closest approach to Kuiper Belt object Ultima Thule, the New Horizons spacecraft has sent back the first images that begin to reveal Ultima's shape. The original images have a pixel size of 10 kilometers (6 miles), not much smaller than Ultima's estimated size of 30...

Despite the various governmental breakdowns attendant to the event, the New Horizons flyby of Ultima Thule is happening as scheduled, the laws of physics having their own inevitability. Fortunately, NASA TV and numerous social media outlets are operational despite the partial shutdown, and you'll want to keep an eye on the schedule of televised events as well as the New Horizons website and the Johns Hopkins Applied Physics Laboratory YouTube channel. Image: New Horizons' path through the solar system. The green segment shows where New Horizons has traveled since launch; the red indicates the spacecraft's future path. The yellow names denote the Kuiper Belt objects New Horizons has observed or will observe from a long distance. (NASA/JHUAPL/SwRI). We're close enough now, with flyby scheduled for 0533 UTC on January 1, that the mission's navigation team has been tightening up its estimates of Ultima Thule's position relative to the spacecraft, key information when it comes to the...