Boldly going …

On August 25th 2012, while the eyes of the global space community were focused almost entirely on the happenings in a crater on Mars, a significant event took place approximately 18 billion kilometres (11 billion miles) from Earth. Voyager 1 passed through the heliopause, the boundary between what is regarded as the “bubble” of space surrounding the solar system (heliosphere) which is directly influenced by the Sun, and “true” interstellar space.

The heliosphere and its component elements
The heliosphere and its component elements

That the spacecraft might be nearing the so-called “bow shock” area where the solar wind meets interstellar space was indicated by engineers and scientists working on the Voyager project in June 2012; however, it was not until September 2013 that NASA JPL felt confident enough in the data they’d received to confirm that Voyager 1 had in fact passed into interstellar space in August 2012, the first man-made object to have done so, some 35 years after having been launched from Earth in what was a highly ambitious programme of deep-space exploration.

The Voyager programme actually had its roots in a much more ambitious programme, the so-called Grand Tour. First put forward by NASA engineer Gary Flandro,  The Grand Tour proposed the use of a planetary alignment which occurs once every 175 years, together with the potential to use the gravities of the planets as a means by which space probes could explore the outer planets of the solar system.

The idea of using gravity of the planets to help propel a space craft had first been realised by a young mathematician, Michael Minovitch, in 1961. With the aid of the (then) fastest computer in the world, the IBM 7090, Minovitch had been trying to model solutions to the “three body problem” – how the gravities of two bodies (generally the Earth and the Sun) influence the trajectory and velocity of a third (generally a comet or asteroid) moving through space; something astronomers and mathematicians had long wrestled with.

The men behind Voyager: Michael Minovitch (l), circa 1960; Gary Flandro (c), circa 1964; and Ed Stone (r), the project scientist and long-time advocate of the mission, circa 1972 (Stone later when on to serve as NASA's Director at JPL)
The men behind Voyager: Michael Minovitch (l), circa 1960; Gary Flandro (c), circa 1964; and Ed Stone (r), the project scientist and long-time advocate of the mission, circa 1972 (Stone later went on to serve as NASA’s Director at JPL)

Through his work, Minovitch showed how an object (or space vehicle) passing along a defined trajectory close to a planetary body could, with the assistance of the planet’s gravity, effectively “steal” some of the planetary body’s velocity as it orbited the Sun, and add it to its own.

At the time, his findings were received with scepticism by his peers, and Minovitch spent considerable time and effort drawing-up hundreds of mission trajectories demonstrating the capability in order to try to get people to accept his findings. But it was not until 1965, when Flandro started looking into the upcoming “alignment” of the outer planets (actually a case of the outer planets all being on the side of the Sun, rather than being somehow neatly lined up in a row) due in the late 1970s, that Minovitch’s work gained recognition.

Recognising the opportunity presented by the alignment, Flandro started looking at how it might be used to undertake an exploratory mission. In doing so, he came across Minovitch’s work and realised it presented him with exactly the information needed to make his mission possible, and so the Grand Tour was born.

Voyager: the most prominent element of the vehicle is the communitactions dish; below and to the left of this is the nuclear RTG power source; extending out to the top left is the insstrument boom, and to the right the imaging boom and camera system
Voyager: the most prominent element of the vehicle is the communications dish; below and to the left of this is the nuclear RTG power source; extending out to the top left is the instrument boom, and to the right the imaging boom and camera system

This mission would have originally seen two pairs of spacecraft launched from Earth. The first pair, departing in 1976/77 would form the MJS mission, for “Mariner (then the USA’s most capable deep-space vehicle)-Jupiter-Saturn”. These would fly by Jupiter and Saturn and then on to tiny Pluto; while a second pair of vehicles launched in 1979 which would fly by Jupiter, Uranus and Neptune.

Budget cuts at NASA following Apollo eventually saw the Grand Tour scaled-back to just two vehicles, Voyager 2 and Voyager 1, but the overall intent of the mission remained intact under the Voyager Programme banner, now led by Ed Stone. In the revised mission, both spacecraft would perform flybys of Jupiter and Saturn, with Voyager 2 using Saturn to boost / bend it on towards Uranus and from there on to Neptune, while Voyager 1 would approach Saturn on a trajectory which would allow it to make a flyby of Saturn’s huge Moon Titan, of significant interest to astronomers because of its thick atmosphere.  This route would preclude Voyager 1 from reaching Pluto, as it would “tip” the vehicle “up” out of the plane of the ecliptic and beyond even Pluto’s exaggerated orbit around the Sun, and push it onto an intercept with the heliopause.

Continue reading “Boldly going …”

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Facebook support coming to the SL viewer

Eagle-eyed (or given his avatar, should that be owl-eyed? :)) Daniel Voyager spotted a pointer that a degree of Facebook support is coming to the SL viewer for those who already have a Facebook account.

The new capability is called Second Life Share, which is being aimed at the viewer 3.6.6  code base (although it isn#t a part of the latest Materials RC viewer, 3.6.6.280797 released on September 11th).

When it does appear, the capability will be opt-in, an important point to remember. Nothing happens vis-a-vis the viewer and Facebook unless you want it to happen (and you have a Facebook account). It will apparently consist of a new viewer floater, itself comprising a number of tabs:

  • Account Tab: will allow those with a Facebook account to connect their SL account to it for the purposes of posting from SL to Facebook
  • Check-in tab: will allow someone to share the SLurl for their current in-world location via Facebook, together with a short comment on the location and a map image if they wish
  • Status tab:  will allow someone to share a text comment with friends via Facebook
  • Photo tab: will allow someone to upload a snapshot to their FB account. As with the current Profile Feed option in the snapshot floater, the resolution of the image can be selected at upload (minimum 800×600), and an optional SLurl / comment can be included with the image.

Details on the capabilities are outlined in Viewerhelp on the wiki, which also references a new Knowledge Base entry, Second Life Share. Unfortunately, clicking the link generates a 404 error, and a search of the Knowledge Base at the time of writing did not yield and further relevant results. I’ve included the link here in anticipation of the issue being fixed by LL.

Whether the title of the new functionality is “Second Life Share” is indicative that it may be extended to include other social media options remains to be seen. It will also be interesting to see what it might mean for the future of the snapshot floater – if anything at all – if this is the case.

I’ll follow-up on this post once the new functionality is visible.

SL projects update week 37 (2): particle capabilities – viewer release imminent

Update: The maintenance release viewer with the particle capabilities is now available – version 3.6.6.2.80939 – release notes and download.

Server and RC Deployments

As always, please refer to the week’s forum deployment thread for news, updates and feedback.

In a change to the usual server-side deployments, the Main channel and all three RC channels have had their deployments and restarts made on Tuesday September 10th. The reason for the single pass was to apply updates server-side relating to recent Vivox service maintenance.

Details of the updates can be found in part 1 of this week’s update.

Server and RC Deployments Week 38

While the final decisions on deployments will not be made until that start of week 38 (week commencing Monday September 16th), it currently appears as if the following are likely to form part of the deployments:

  • The server-side HTTP updates will be promoted to the Main channel
  • A small server maintenance release will be deployed to at least one RC, which includes a number of crash fixes and an update to parcel access priorities “making it so that avatars who are on the ‘allowed’ list can bypass some of the other access restrictions (payment info on file was listed specifically)”

Particle System Viewer Imminent

Back in week 12, the Lab indicated that the SL particle system would be getting new capabilities, specifically:

  • Glow
  • Ribbon effects
  • Blending options.
Ribbon particle example

The server-side support for these capabilities was duly deployed, but have since been awaiting the viewer-side support in order to be accessible to users.

Commenting on the situation at the Server Beta meeting, Maestro Linden indicated that a release candidate viewer should be appearing with the necessary viewer-side support for the new LSL particle functions and parameters on Friday September 13th.

In preparation for the release, Maestro has also updated the wiki with details of the new particle parameters.

“The new particle glow options are pretty simple,” he said. “If you look at the wiki page, we’ve just added PSYS_PART_START_GLOW and PSYS_PART_END_GLOW, which take a float in the 0.0 to 1.0 range. It basically looks the same as the prim glow setting on prims.”

He went on, “particle blending takes 2 parameters, PSYS_PART_BLEND_FUNC_SOURCE and PSYS_PART_BLEND_FUNC_DEST, and each of those takes one of the 8 ‘values’ listed underneath, so there are actually 8*8 = 64 blend options! You can do crazy things, like having particles invert the thing underneath.

“Anyway, the blend parameters are pretty technical.  It’s basically exposing OpenGL’s glBlendFunc to LSL. And the main  glBlendFunc documentation at http://www.opengl.org/sdk/docs/man/xhtml/glBlendFunc.xml goes into the details better than I can.”

For those who can’t wait for the RC viewer with the necessary support to appear, an autobuild version is available.. However, keep in mind this is a test build for the capability, and as such is liable to be behind the curve compared to the RC version in terms of bug fixes, etc., so be sure to update to the RC version when it appears on the wiki page. The RC version is now available.

An example of how the now ribbon capabilities might be used in SL, showing the arc of the sword through the air, supplied by Maestro Linden (courtesy of Hollowfear.com)

The new ribbon capability should allow for much better particle effects for things like ropes and chains links between objects (amount other things), using a ” go-from” prim/position (the prim centre), and a “go-to” prim/position (defined by PSYS_SRC_TARGET_KEY), the advantage being there would no longer be any gaps in the particle stream. However, there may be times when the ribbon effect may not be facing your camera (so there may be times when you need to reposition your camera in order to see the effect).

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