Of volts and launches and looking for answers in the air

CuriosityIt’s been an eventful week for Mars-related activities. After suffering a software reset on November 7th, as reported on in my last MSL update, the rover Curiosity experienced a second problem on November 17th.

This was caused by an unexpected voltage change being detected in the vehicle, described as a “soft” short, meaning that electricity is unexpectedly passing through something that is partially conductive, and in difference to a “hard” short, such as one electrical wire contacting another.

The short was first noted as a voltage difference between the chassis and the 32-volt power bus that distributes electricity to systems throughout the rover. Data indicating the change were received on Sunday November 17th, Curiosity’s 456th Martian day. Prior to the short occurring, the voltage level had been a consistent 11 volts; however, the data received indicated it has dropped to 4 volts.

While there was no immediate danger, as the rover’s electrical system is designed with the flexibility to work properly across a range of voltages – a design feature called “floating bus” – the decision was taken to suspend science operations while matters were investigated.

The Liberty 1909 penny mounted on Curiosity’s flank and used to calibrate the Mars Hand Lens Imager (MAHLI) mounted on the robot arm, as imaged on Sol 411 (October 2nd, 2013) at MAHLI’s highest resolution, some 14 micrometres per pixel. Note the dust and clumps of dust adhering to the coin despite it being vertically mounted on the rover

This was actually the second soft short Curiosity has experienced.  The first occurred on the very day it arrived on Mars – August 5th/6th 2012 – when the bus-to-chassis voltage dropped from about 16 volts to about 11 volts. This was thought to be related to explosive-release devices used for deployments shortly before and after the landing, but did it not and has not interfered with the rover’s operational capacity or capabilities.

Although the voltage change did not pose any immediate threat, and the vehicle did not enter a safe mode status, nor was it related to the earlier software reset, such soft shorts can reduce the robustness of the rover’s electrical systems for tolerating other shorts in the future. Further, they can indicate a possible problem in whichever component is the site of the short. Hence the decision to suspend science operations and take time to check some of the possible root causes for the voltage change.

Subsequent analysis revealed that the voltage drop occurred intermittently three times in the hours before it became persistent. Some six days were spent in root cause analysis using data returned by the rover, which saw a number of potential causes suggested by mission engineers eliminated. This resulted in the most likely cause being identified as an internal short in Curiosity’s power source, the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG or RTG for short).

Due to resiliency in the RTG design, this type of short does not affect operation of the power source or the rover. In fact, similar generators on other spacecraft, including NASA’s Cassini at Saturn, have experienced shorts with no loss of capability, and testing of an Earth-based RTG over many years found no loss of capability despite the presence of these types of internal shorts.

As a result of these findings, the rover was commanded to re-start science activities on November 23rd, and data returned from Curiosity’s onboard monitoring systems indicated that voltage levels had successfully returned to levels prior to that of the November 17th incident, a sign which is again indicative of an internal short within the RTG systems.

The resumption of science activities was marked by the rover delivering a further sample of rock cutting gathered some 6 months ago from an outcrop dubbed “Cumberland” in the “Yellowknife Bay” area of Gale Crater. A number of samples from the outcrop have already been analysed by the Sample Analysis at Mars (SAM) suite of instruments, which has the flexibility to be able to carry out such analyses a number of different ways, allowing significantly more data to be gathered on samples of the same rock gathered and stored by the rover.

Continue reading “Of volts and launches and looking for answers in the air”


LL issue notice on concierge phone and chat support for Thanksgiving Day

secondlifeThis week is Thanksgiving week in the United States, which means that not only will Americans be celebrating on Thursday and the weekend, it also means some disruption to the modus operandi in Second Life.

As I’ve noted in mt recent SL project updates, this week is a code freeze week, which means there are no planned server deployments or viewer RC releases. It also means that there will be some reduction in support for users in order to allow staff to enjoy time off with their families. In particular, concierge phone and chat support will be closed on Thursday November 28th, as announced in a Grid Status update which reads:

Concierge phone and chat support will be offline this coming Thursday, 28 November, so that team members can spend the Thanksgiving holiday with their friends and family.  Both services will close at midnight Wednesday evening and will re-open at 8am Pacific on Friday morning.

All other Customer Support departments will be staffed at customary levels.

SL projects update week 48: region crossings, scripted camera and region restarts

Server Deployments week 48

As this is Thanksgiving week in the USA, it is a code freeze week with no scheduled deployments for the grid. Deployments will resume in 49.

It was a quite Simulator UG meeting in terms of news from LL due to this being Thanksgiving week (image: stock)
It was a quite Simulator UG meeting in terms of news from LL due to this being Thanksgiving week (image: stock)

SL Viewer

There are no planned RC releases or updates  for week 48, again because of the Thanksgiving code freeze.

Oz Linden is, however, working on getting another maintenance RC together in the near future, although it’s not clear exactly what this will contain at this point in time.

There have also been reports of issues with test versions of viewers built using the latest Sunshine External repository (the SSA “polish” code and AIS v3). The exact cause of the problems is not known, but it is leading to a high number of Current Outfit Folder mismatch issues on Windows. A request has been passed to the Lab to check the automated build process in order to help ascertain if there is a problem in the code, or whether an issue in merging the code is causing problems. These issues don’t affect any released versions of viewers, only those using the latest SAA / AIS v3 code for testing purposes.

Default Object Permissions

A number of TPVs include the ability to specify the default permissions applied to a new prim object (cube, cylinder, torus, etc.) on creation. A similar capability is being developed for the LL viewer (STORM-68) by Jonathan Yap, a long-time contributor to the viewer. However, this work also requires updates to server-side  capabilities, and Andrew Linden is now looking into this, and at the moment is specifically trying to figure out how to propagate the default perms through teleports and region crossings.

Other Items

Region Crossing Issues

The three RC channels are all running the same simulator version, which includes a fix for “Sim crossing on vehicle fails when parcel at opposite sim border is full.” (BUG-4152). Describing the issue at the Simulator User Group meeting on Tuesday November 26th, Simon Linden said, “The server was doing a parcel check at the wrong location … you’d cross, and at one point it would check a parcel based on the new region coordinates in the first region.   If that happened to be a full parcel, it failed.” This issue has been reported as occurring on Main channel regions as well, under a variety of  reports including SVC-8007. As such, it is hoped that when the package currently on the RCs is promoted to the Main channel in week 49, these issues may also be rectified.

In the meantime, and to test whether the fix may work for SVC-8007, the mainland region of Epirrhoe has been moved to the Magnum RC to allow vehicle crossings to be tested between it and the neighbouring region of Jodis, which has been a crossing which has experienced repeated issues with SVC-8007 for the SLRR.

llSetCameraParams([CAMERA_DISTANCE, x])

Many vehicles of all types in SL use llSetCameraParams to establish a “follow camera” which allows the vehicle to be effectively guided by the driver / pilot.  However, there has been a long-standing issue the CAMERA_DISTANCE  rule, which is clamped to distances far shorter than draw distance. This can make it next to impossible to create a scripted follow camera for very large vehicles such as realistically sized spacecraft, airships and ships.

Clamping with CAMERA_DISTANCE can lead to issues when trying to script a follow cam for very large vehicles using
Clamping with CAMERA_DISTANCE can lead to issues when trying to script a follow cam for very large vehicles using llSetCameraParams

The original JIRA (SVC-3499) was closed as “Won’t finish”. However, commenting on the matter at the Simulator User Group meeting, Andrew Linden said:

If we were to expand the clamp limits then some poorly written scripts will change behaviour. How much do we care about breaking such poorly written scripts? And… I wonder why it was clamped so tight? It would be nice to ask around to see if anyone remembers why some limits were set … Well, it would be possible to expand the distance limit and test to see how it works with different limits. If nothing breaks too bad, then perhaps we could ship it.

A new BUG report has been filed as a feature request for this to be looked at (BUG-4594), which is likely to be looked-at the next time feature requests are sorted, and quite possibly passed to Maestro Linden.

Region Restart and Visibility Issues

An unusual issues has been reported which appears to be related to region restarts and visibility, but it only noticeable on regions which have multiple neighbours, all of which are restarted at more-or-less the same time (within about a minute of one another). The problem can be broken down into a number of related points:

  • Observers are standing in region A, which is surrounded by regions B, C, and D – all of which are restarted at pretty much the same time
  • Following the restart, there is a high probability that some or all of regions B, C, and D will not be visible to those observers on region A (which was not restarted), and they show-up as red on the mini-map – something which has been confirmed on both the SL viewer and Firestorm
  • However, anyone entering region A after the restart will see all of regions B, C, and D as expected. Similarly, anyone on region A at the time the other regions restarted can resolve problems by relogging
  • Those observers who were in region A at the time the surrounding regions were restarted are able to fly into any of them which are showing as red on the mini-map, and although nothing physically renders for them, they will experience object collisions. Furthermore, it is possible to exit the “red” regions on the mini-map and fly into the void where no regions actually exist.

In tests with a specific set of regions, the above issues occurred in 8 out of 12 tries. That there is a unique problem with the regions on which the tests were carried out has been pretty much discounted. Whirly Fizzle, who has been poking at the issue with a number of people, provided a screen capture show how her alt managed to fly through a “red” zone and into the void where no region exists.

Following a region restart, Droom is shown in red on the mini-map, to observers located in Mote (lower left on the mini-map) at the time of the restart. However, these observers were able to fly through Droom, although nothing would render for them (but collisions would occur), and then into the void space where no region exists (image courtesy of Whirly Fizzle, click to enlarge)

Commenting on the matter, Simon Linden said, “It sounds like it’s getting confused and not realizing the old connection went away …  I’d bet on the timing.”

Agreeing with this point of view, Andrew added: “If Region A thinks your viewer can already see into Region B, it wouldn’t initiate the connection,” hence why relogging would appear to fix the issue for those experiencing the problem and those arriving in the region after those around it have been restarted: as you arrive in the region, it (re-)initiates the connection between the  viewer and the surrounding regions. This is also why people encountering the situation can enter void areas where no regions exist, as Andrew also explained: “The region you’re on expects the other region to inherit your avatar, o it lets you walk beyond the region boundaries until the other region picks you up. But if the exchange never completes, you get to walk around outside of the region boundaries for a while.”

This can be seen in the image Whirly supplied: while she is clearly in a void space where no regions exist, the title bar of her viewer still reports her as being in Mote (her “region A” during the test), because the “hand-off” between Mote and Droom (shown in red on her mini-map) never completed.

Andrew recently fixed another issue related to connections to neighbouring regions, and has offered to look into the matter himself to find out what is going on and how it can be rectified.

Can you get 400+ decor items with one prim? PrimPossible!

Sculpts are not everyone’s cup of tea, it has to be said; but even in the age of mesh, and despite their cost in terms of download and rendering, etc., they remain popular for a range of things: furniture, plants, building elements and so on.

One person who has turned the sculpt into something of a creative art form is Ample Clarity. I’ve covered his work a number of times in this blog, and I confess that I’m a big fan of his top-of-the-line concert grand piano, which still graces my home (as does one of his furniture suite, a patio lounger and a bedroom set!).

Now he’s done it again, with the PrimPossible Unlimited Decor Menu and HUD. This is a single sculpted prim which, via a menu (and a HUD to speed the rezzing process in the wearer’s view) can become any one of over 100 works of art or one of 300 rugs, or one of 42 different potted plants, one of 8 different lamps, a guitar, a violin, a dressing table, a desk with a computer, one of a number of tables, a telescope… the list goes on.

The PrimPossible Decor Menu  - one sculpt, many shapes (and sizes and finishes)
The PrimPossible Decor Menu – one sculpt, many shapes (and sizes and finishes) – image courtesy of Ample Clarity

This is quite a remarkable feat; and for those who are pushed for space, land impact-wise, the system potentially offers a neat way of flicking between various furniture options without having to worry about the associated prim counts.

The decor menu comes in two variants. The basic model is no Mod / Copy / Transfer, and costs L$100, allowing you to one create and display one item at a time. This is ideal if you’re only interested in using it for a single rug or painting, as it still means that you can change the appearance of the rug or painting to suit your mood. However, the second version is Copy, no Mod / Transfer, and costs L$800. Being copyable means that you can use shift-drag to create multiple versions and then change each of them to create a new object in your home.

As well as offering an impressive range of options and shapes, the menu also controls the tint / glow / shine associated with an object; so that lamps, for example can be made to look as if they are “on” by adding a level of glow. the menu also offers resizing along all three axes and for those who know what they are doing, to add custom textures – just do remember that the objects are all one prim, so care needs to be taken to achieve a desired result.

The glow options can simulate a lighting effect in the lamps
The glow options can simulate a lighting effect in the lamps

There are obviously some limitations to the system; individual items are unscripted, obviously, and as they are formed out of a sculpt, fine detailing on some can be a little rough in places; a coffee cup which is a little more octagonal than round, for example, while the headstock on the guitar is oddly angled. Given how far Ample is pushing the sculpt, little oddments are perhaps not surprising, and they don’t detract from the overall usability of the system.

Certainly, and as mentioned above, for those on a prim budget, the copyable version of the Decor Menu offers a nice degree of flexibility for adding decorative touches and furnishings to your home; for my part, I find the decor lamp particularly attractive, and the piles of books help add a “lived-in” feeling to a place. All-in-all, an intriguing addition to the PrimPossible range.

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