Thursday, September 27, 2012

The importance of keeping track

Got home from my trip to find a rejection letter from SciFiction in the mailbox.

It was a form letter and did not list my story title on the page. I checked my records and Sonar says I have nothing at SciFiction. But they couldn't have gotten one of my SASE's... so I have no clue what story they're rejecting.

Let this be a lesson to you. I now am hesitant to send any more of my existing stories to SciFiction because of this one mistake, as you do NOT want to send the same story to a magazine twice.

I will try my hardest to get an ISBW up today. It's already planned out, I just have to *do* it.

Wednesday, July 4, 2012

Fascinating article

In April 2001, NASA's Jet Propulsion Laboratory (JPL) awarded $1-million Mars Sample Return (MSR) study contracts to industry teams led by Ball Aerospace, Boeing, TRW, and Lockheed Martin (LM). In Phase 1 of the study, the four teams independently assessed a range of MSR mission concepts. JPL stipulated that all should include a rover capable of gathering samples across several square kilometers of Mars's surface over several months. The MSR mission would begin no earlier than 2011. In Phase 2, each team fleshed out one or two of its concepts to permit cost estimates to be made and to identify areas requiring technology development.

The LM industry team looked at three concepts: Libration Point Rendezvous (LPR), Low Mars Orbit (LMO), and Deep Space Rendezvous (DSR). In LPR, the Mars Ascent Vehicle (MAV) bearing the Mars samples would rendezvous with an Earth-Return Vehicle (ERV) waiting in a loose orbit about the Sun-Mars L1 point, about one million kilometers nearer to the Sun than Mars. LMO was the traditional Mars Orbit Rendezvous (MOR) MSR architecture, which saw the MAV meeting up with the ERV in close Mars orbit. DSR would see the MAV rendezvous with the ERV as the latter zipped past Mars on a flyby trajectory that would carry it back to Earth. DSR outwardly resembled the FLEM and piloted flyby/MSSR concepts of the 1960s; according to study participant Benton Clark, however, his team was unaware of the 1960s plans when it developed DSR.

In LPR and LMO, the MAV could remain on Mars for months waiting on the JPL rover to gather samples; DSR, by contrast, enabled only a short surface stay before the ERV flew past Mars, so did not enable effective use of the rover's capabilities. Thus, in Phase 2, LM narrowed its focus to the LPR and LMO concepts.

Even as the contractor teams performed their studies, however, budget pressures forced changes in NASA's Mars plans. Aided by a Science Steering Group, JPL trimmed its MSR requirements to permit a cheaper "groundbreaking" "science floor" MSR mission in 2013. Sample collection would be by robot arm mounted on the lander, not by rover. This would reduce to a few weeks the time the lander needed to stay on Mars. The shorter stay-time led the LM team to revive the DSR MSR concept.

The company scheduled launch of its DSR MSR mission for September 14, 2013. The DSR MSR spacecraft would consist of an 810-kilogram Earth Return Vehicle (ERV) and a 2078-kilogram lander with Mars Ascent Vehicle (MAV). A General Dynamics Atlas 5-521 rocket would place the spacecraft on a low-energy Type IV trajectory needing nearly 32 months to reach Mars. The ERV, based on the LM Mars Odyssey spacecraft design (top image above), would provide course correction propulsion and electricity during the long voyage.

The MSR spacecraft would approach Mars on a collision course. The lander, encased in a 4.5-meter-diameter conical aeroshell, would separate from the ERV on February 4, 2016, four days out from Mars. The ERV would then briefly fire its rocket engine to place itself on a Mars flyby trajectory.

On February 8, 2016, the MSR lander would enter the martian atmosphere directly (that is, without first entering Mars orbit). Atmosphere entry, descent, and landing would benefit from experience and software developed during the 2009 Mars Science Laboratory mission, the LM team stated (bottom image above). Touchdown would take place within 10 kilometers of a pre-selected target near the beginning of martian northern hemisphere summer.

The DSR MSR lander would include three landing legs, six descent engines, twin 10-sided solar arrays, and a "Sample Handling Workbench" with twin robot arms. The arms would fill small cylindrical sample containers with a total of 0.5 kilograms of rocks and dirt.

In keeping with JPL's instructions, the LM-led team devoted much attention in its "science floor" study to preventing possible martian microbes from reaching Earth. Each sample container would be placed into an "ashing chamber," where heat would sterilize its exterior, then would be pushed into a "bagging chamber," where it would be sealed inside a cylindrical sleeve-like plastic bag. After bagging, the container would ride an elevator to the cylindrical Sample Canister Assembly (SCA) in the MAV's conical nosecone. Sample loading would occur within a "Bio Enclosure" "cocoon" pressurized above Mars's atmospheric pressure to ward off Mars dust and microbes that might infiltrate the SCA.

On March 1, 2016, 20 days after landing on Mars, the 266-kilogram two-stage MAV would blast skyward from a launch tube at the center of the lander's triangular frame. A modestly enlarged Star 17A motor with 146.2 kilograms of solid propellant would form the MAV's first stage, and would form its second stage. Cold-gas thrusters would provide attitude control. Mars atmospheric friction heating during ascent would help to sterilize the MAV's exterior. Prior to first-stage separation, the MAV second stage - a Star 13B motor with 54.2 kilograms of solid propellant - would be spun up to 150 rotations per minute to provide gyroscopic stabilization.

When the MAV second stage exhausted its propellant, it would be about four million kilometers from the ERV. Solar cells on the MAV nosecone would power a radio transponder to enable tracking. On March 6, 2016, the ERV would fire its rocket motor to place itself on course to intercept the passive MAV second stage and SCA.

About 80 days after MAV launch (June 1, 2016), when the MAV second stage and ERV were about one million kilometers apart, the ERV would perform another rendezvous maneuver. The ERV would then intercept the MAV second stage about 20 days later. The SCA would eject from the MAV nosecone and the ERV would scoop it up using a "funnel" that would channel it into a "vault" in the Earth Entry Vehicle (EEV). The team explained that its EEV design was based on the Stardust and Genesis sample return capsule designs.

The ERV would then begin a series of Earth targeting maneuvers. Earth return would occur on November 13, 2016. The ERV would spin up and release the EEV, then fire its rocket motor to ensure that it miss Earth. This would help prevent any martian microbes it carried from contaminating Earth. If the ERV failed, timers on board would automatically fire a solid-propellant rocket motor to divert it from Earth impact. If telemetry from the EEV indicated that the SCA had leaked, the samples would be heat-sterilized to prevent biological contamination of Earth.

The EEV would enter Earth's atmosphere directly, cast off its backshell and heatshield, and deploy a parachute. If the EEV broke up during Earth atmosphere entry, the vault containing the SCA would serve as a backup entry vehicle capable of surviving Earth impact. Assuming a successful EEV reentry, however, a helicopter trailing a hook would snag the parachute in midair in the manner planned for September 2004 Genesis and January 2006 Stardust sample recoveries. The industry team stated that the probability of a successful midair recovery was 99.9%, and that this could be further enhanced by additional testing and helicopter pilot training. After recovery, the EEV would be placed inside a containment carrier and transported to a Bio Safety Level 4 handling facility.

The LM team briefly considered a "split" DSR scenario in which the lander and MAV would leave Earth in September 2013, and the ERV would leave Earth in November 2016, after the MAV had successfully placed the SCA bearing Mars samples into orbit around the Sun. The split scenario called for a "long-life SCA" and a three-stage MAV. The additional MAV stage would be used to refine the SCA's orbit, making it easier for the ERV to locate.

The team estimated that, at $791 million, its baseline DSR MSR mission would cost $480 million less than its LPR mission. The largest single savings ($72 million) would be achieved by deleting all lander science instruments. Switching from a Delta 4050H rocket to an Atlas 5-521 would save $64 million, and dispensing with the rover would save $51 million. The industry team did not include in its cost estimate the $135-million "Pre-Project Technology Development Program" it believed to be necessary to help ensure a successful DSR MSR mission.

In September 2004, after a successful Earth reentry, the Genesis sample return entry vehicle failed to deploy its parachute and crashed in Utah, breaching its sample container (image below). U.S. space policy changes, meanwhile, caused NASA to push its target date for the launch of the first U.S. MSR mission to the late 2010s or the 2020s.

source: http://robotexplorers.blogspot.com/

Thursday, November 30, 2006

am I honest?

Prof Me is moving. Reading her post today about blogging honesty and assuming a character moved me to a little soul-searching: Why do I do this? Why do I make the effort to write on this blog when there are plenty of other writing projects to keep me busy? Besides the why, is there a question of who? Might I have taken on a persona that doesn't ring true to the real me?

I started this blog over two years ago - a fact that stuns me every time I think of it. I started because I was interested in weblogs; I was considering them as part of the research for my dissertation and I didn't think I could do that without first experimenting with the concept. The first few posts were rather stilted (since I wasn't writing for any real purpose) but I gradually slid into academic mode: the blog became a way for me to think through dissertation issues - the research, the writing, the meetings, the literature. Like PM mentions, though, the blog "quickly evolved into a more personal statement" and I was writing whatever came to mind.

Two years later, why do I keep writing? Sure, I like using the blog to work through things as I type - but I could easily write in a journal. Yes, the blog gives me a place to vent about all sorts of things, large and small - but I could talk to a wall if the issue is just venting. Okay, I have found that the physical act of making myself think coherently in this informal space guarantees that I write something every day, which is necessary for my brain - but I could keep a notebook or scribble on a scratchpad to keep those juices flowing.

When it comes down to it, I write because of the community I feel here. Selfishly, I like the feeling of friendship that comes from writing, receiving comments, reading other blogs, leaving comments; I have a group of friends - even without knowing their faces or sometimes even their names - and I want to talk to them. I like that new friends might pop up; I like that I can ask questions and get answers; I like that I can have a bad day and hear the virtual nods from everyone who's suffered the same. This blog isn't the same blog that I started two years ago but I think I'm okay with that.

The question of "honest" blogging is harder to answer. Is this me? If you met me for coffee (or tea, as the case may be), would you make the connection between the me in front of you and the me on your computer screen? I'd like to think so. I "talk" here, so I feel like this is my voice. The turns of phrase, the muttered asides, the self-deprecating humor - that's me over lunch, too.

So, why blog anonymously? If I think of this as a community and many of you as friends, why not just open it up and say who I am, where I am, what I do? You know, I have a hard time answering that. I've thought about it at times over the past two years but I don't have a clear response. There are the issues of protecting myself from possible university retribution, perhaps (I definitely wouldn't link to my blog from my faculty website, so that perhaps may be more definitive than I want to admit). However, the best answer I can give is this: I'm still figuring out who I am. Right now, phd me identifies me as clearly as my real name, at least in my mind, and it doesn't come with some of the baggage that accompanies my given name. It's like meeting someone for the first time, offering your hand and starting a conversation; at that minute, you are only what exists between you. It isn't that you're creating a new persona, it's that you get to present a fresh you, the real you. Using my real name provides info that may or may not accurately present who I am - not the name itself (I'm not descending from a royal line or anything) but the accompanying bits that are easily interpreted to form a perception - what I look like, what I do, where I live.

That's the best I can do, and it may or may not make sense.

Wednesday, November 29, 2006

and sometimes I'm not so sure

Another student meeting. Another successful discussion about the research project. I'm not leaving with my warm and fuzzy butterflies this time, though.

This student has had a rough semester; I knew that, on one level, but without knowing anything else, I just had a record of class absences and missed assignments leading to possibly failing the course. I stopped the student after class the other day and suggested (okay, told) that my office hours today would be an excellent time to talk to me. We'd had a similar discussion earlier in the semester, so I was a little miffed that we had to rinse and repeat, but such is my job, right?

I handed over the Kleenex five minutes into our conversation. This student has had to manage a personal issue and two major family traumas this semester, on top of an 18-hour courseload. The student was very apologetic in explaining that classes were the only flexible option in all of that and the intention wasn't to blow off anything but there was just too much to handle at one time, literally and emotionally.

I can only imagine. I wish I'd known earlier because, I assure you, I would have handled my irritation about missed classes quite differently. At the same time, I'm a private person - I wouldn't have approached any of my professors with something like this, either - so I can understand the reluctance to talk about personal issues. The student is headed back toward solid ground academically now and there was laughter before we finished, so I feel okay about things in general.

I just needed to remember, it isn't really about the classwork after all.

sometimes I am good at what I do

A student came this morning to talk about her final research project. She wasn't as lost as she thought, but she couldn't quite grasp how everything was supposed to come together (and don't we all know that feeling!). I drew diagrams; I asked questions; I used props; I scribbled down notes. She nodded and asked questions and explained where I didn't make sense and, in the end, left with a much better idea of how to tie the whole project together. I ran across campus to grab something to drink after she left and on the way back, I thought,
"I like this part of my job. I like sitting down with students to work through roadblocks; I like the push and pull required of working one-on-one with students; I like being able to challenge and support my students - and I'm good at it. Maybe it doesn't count for anything in the grand scheme of tenure and promotion - but I'm good at it. Maybe I don't do everything well - but I am good at this."
Self-aggrandizing, perhaps, but sometimes, it's nice to feel like you do something well.

I've got nothing

Well, the headache is gone but I still find myself with nothing very interesting to say. Shall I update you on the not-very-interesting, then?

I had a 9:30 meeting with a fellow prof this morning (and I was running late, as I always seem to be these days). I prepped for class and managed a few emails before a student came to talk about the final project (now they want to talk!). Class went well; we had an interesting topic for discussion and they managed to stay awake for my - very short - lecture (I had good examples). I finished up my grant proposal for the study abroad program and sent it off (one thing off the to-do list - whoo) before I met a prof from the department for a semester check-in. After a quick stop at the grocery store, home to grade student papers before finally fixing dinner and collapsing in front of the TV to do nothing productive.

Fascinating, I know.

And I'm curious as to whether anyone is actually getting my posts over this last week. I have a sneaking suspicion that the site feed isn't working.

Update: Thanks to Prof Mama for letting me know comment moderation was somehow enabled on my blog. There have been some weird happenings in my personal blog-land lately; I'll just blame it on the techno-elves.

Tuesday, November 28, 2006

so - much - grading

Aside from making revisions to a grant application this morning, I've been grading all day. All day. Obviously this is a common complaint at the end of the semester, and since I'm the one that assigned the work in the first place, I have only myself to blame. However. Oh well, at least they're writing interesting stuff - and by interesting, I mean both intellectually stimulating and downright laughable.